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The tumor described here as lipofibromatosis is a rare pediatric neoplasm that has been variously interpreted as a type of infantile or juvenile fibromatosis, a variant of fibrous hamartoma of infancy, and a fibrosing lipoblastoma. This report details the clinicopathologic features associated with 45 cases of this soft tissue entity. The study group consisted of 32 males, 12 females, and one person of unstated gender. The patients presented with a soft tissue mass (range, 1-7 cm) involving the hand (n = 18), arm (n = 8), leg (n = 7), foot (n = 6), trunk (n = 5), or head (n = 1). Eight tumors were evident at birth. The individuals ranged in age from 11 days to 12 years (median age, 1 yr) at the time of initial biopsy or resection. Microscopic examination revealed abundant adipose tissue with a spindled fibroblastic element that chiefly involved the septa of fat and skeletal muscle. The process generally did not cause extensive architectural effacement of fat as is common with conventional fibromatoses, and it did not have a primitive nodular fibromyxoid component as is characteristic of fibrous hamartoma of infancy. The fibroblastic element exhibited focal fascicular growth and typically had limited mitotic activity (< or = 1 mitosis/ 10 high-power fields) and cytologic atypia. Oftentimes, small collections of univacuolated cells were present at the interface between some of the fibroblastic fascicles and the mature adipocytes. The tumors entrapped vessels (n = 45), nerves (n = 44), skin adnexa (n = 16), and skeletal muscle (n = 18). Focal immunoreactivity was present in some tumors for CD99, CD34, alpha-smooth muscle actin, BCL-2, and less frequently, S-100 protein, muscle actin (HUC 1-1), and EMA. However, no reactivity was detected for desmin (D33 and D-ER- 1 clones), keratins, or CD57. Follow-up data were available for 25 individuals (median follow-up period, 6 yrs 7 mos) with regrowth of the tumor or persistent disease documented in 17 (72%). The following events were more common in the group with recurrent or persistent disease: congenital onset, male sex, hand and foot location, incomplete excision, and mitotic activity in the fibroblastic element. Although it is likely this tumor comprises part of the spectrum of what has been referred to in the literature as infantile/juvenile fibromatosis, its clinicopathologic features and, in particular, its distinctive tendency to contain fat as an integral component, warrant separate classification as a "lipofibromatosis."

We describe 12 patients with a distinctive variant of pleomorphic liposarcoma that histologically shows epithelioid features and focally resembles a solid carcinoma. The tumors occurred in nine men and three women (median age, 63 yr; range, 40-78 yr). Five tumors were in the thigh, two in the chest wall, two in the axilla, and one each in the retroperitoneum, groin, and calf. Most were 15 to 20 cm in maximal diameter. They consisted of sheets of epithelioid-appearing cells with ample, variably eosinophilic cytoplasm, often showing a honeycomb-like pattern of cell borders and little if any collagenous extracellular matrix. Their histologic features often resembled those of renal clear cell carcinoma or adrenal cortical carcinoma, but all showed evidence of adipocytic differentiation, and five also showed focal spindle cell components. One patient whose tumor in the thigh had been originally diagnosed as metastatic renal carcinoma had undergone nephrectomy without a finding of a kidney tumor. All of the cases were positive for vimentin; 6 of 11 cases were positive for S-100 protein, usually focally; 5 of 11 were focally positive for keratins; and all were negative for epithelial membrane antigen, muscle actins, desmin, and CD34. High mitotic activity (mean, 42 mitotic figures per 10 high power fields) and high MIB-1-positive proliferative fraction (>30%) were seen in all of the cases, and nuclear p53 immunoreactivity was detected in five of seven cases. Of the eight patients with complete follow-up, five died of disease (median survival, 6 mo), two died of unrelated causes 10 and 18 years later, and 1 was alive and well 24 years later. The epithelioid variant of pleomorphic liposarcoma is a high-grade tumor that must be distinguished from malignant epithelial tumors, especially in view of the keratin immunoreactivity of some of these neoplasms.

We report 25 cases of a peculiar sclerosing epithelioid variant of fibrosarcoma (SEF) simulating an infiltrating carcinoma. The tumors occurred primarily in the deep musculature and were frequently associated with the adjacent fascia or periosteum. The patients' ages were 14 to 87 years (median, 45). Fourteen were male and 11 female. The tumors were located in the lower extremities and limb girdles (12 cases), trunk (9), upper limb girdles (2), and neck (2). They measured 2 to 14.5 cm in greatest dimension (median size, 7 cm) and were gray to white and firm. Histologically, the lesions were characterized by a proliferation of rather uniform, small, slightly angulated, round to ovoid epithelioid cells with sparse, often clear cytoplasm arranged in distinct nests and cords. In all cases there was prominent hyaline sclerosis, sometimes reminiscent of osteoid or cartilage and foci of conventional fibrosarcoma. Occasional myxoid zones with cyst formation and foci of hyaline cartilage, calcification, and metaplastic bone were also seen. Mitotic figures were generally scarce. Vimentin was detected in 13 of 14 cases, epithelial membrane antigen in seven, S100 protein in four, and neuron-specific enolase in two. Cytokeratins were detected with AE1/AE3 and CAM 5.2 in two cases. Leukocyte common antigen, CD68 antigen, HMB45, desmin, and alpha-smooth muscle actin were negative in all cases. In 13 of 14 cases, 75% or more of the cells stained for proliferating cell nuclear antigen (PCNA). Ki67 immunostaining with MIB 1 showed low proliferative activity in all cases, averaging 5% of tumor cells or less. In all cases, p53 was detected by immunohistochemical methods; bcl-2, an antiapoptosis marker, was detected in more than 90% of the cells in 11 of 12 cases. Ultrastructurally, both the epithelioid and spindled tumor cells had features of fibroblasts. Follow-up in 16 cases ranging from 13 months to 17 years 3 months (median, 11 years 4 months) revealed persistent disease or local recurrences in 53% of patients and metastases in 43%. The metastases were to the lungs (4 cases), skeleton (3), chest wall/pleura (3), pericardium (1), and brain (1). Four patients died of disease, four were alive with disease, two were known to be alive but disease status unknown, and six had no evidence of further disease at last follow-up. The data suggest that SEF is a relatively low-grade fibrosarcoma; yet it is fully malignant despite the presence of histologically benign-appearing foci. The proliferation markers PCNA and Ki67 did not correlate with prognosis.(ABSTRACT TRUNCATED AT 400 WORDS)

We present nine cases of an atypical cellular peripheral nerve sheath tumor, designated plexiform malignant peripheral nerve sheath tumor (MPNST) of infancy and childhood, occurring in five boys and four girls aged 50 days to 13 years (median, 1.5 years). The tumors were located in the lower extremities (five cases), upper extremities (three cases), and the orbital region (one case), and they ranged from 1.5 to 8 cm in size (median, 3 cm). Two lesions were congenital, and another was associated with a history of von Recklinghausen's disease. Follow-up, available in six cases, ranged from 6 months to 15 years (median, 51 months); four patients had local recurrences within 8 to 31 months after excision of the initial lesion, and one with an orbital tumor died of locally invasive disease within 6 months. Histologically, the initial lesions were characterized by a predominantly superficial location within the dermis and subcutis, with occasional extension into deeper soft tissues, had infiltrative or sharply demarcated margins, and resembled entangled or intertwined hypercellular nerve trunks, resulting in a plexiform appearance at low magnification. The nuclei were oval to serpentine with a vesicular chromatin pattern and small basophilic nucleoli; mitoses were seen in all cases and averaged from 1 to 18/10 high-power fields (hpf) (median, 4/10 hpf). Neither necrosis nor vascular invasion was seen. Features diagnostic of plexiform or cellular schwannoma, such as nuclear pleomorphism, Antoni B areas, thick-walled hyalinized blood vessels, and secondary degenerative features were lacking. Other than a prominent plexiform architecture, the lesions were indistinguishable from MPNST occurring in other sites in infants and children. Although none metastasized, the histologic similarity of plexiform MPNST to other childhood MPNST, its relatively high propensity for local recurrences, and its potential to behave in a locally aggressive manner indicate that it is best regarded as low-grade malignant. Overall, the behavior of plexiform MPNST is better than other MPNST in children, probably because of its relatively small size, peripheral and superficial location in most instances, absence of necrosis or vascular invasion, occurrence in young patients, and infrequent association with von Recklinghausen's disease rather than a function of its prominent plexiform architecture. Distinction of plexiform MPNST from cellular and plexiform schwannoma, plexiform neurofibroma, and hamartomatous lesions of childhood is important. Complete excision should be ensured to prevent local recurrences and potential metastases.

We report 20 cases of a peculiar fatty tumor that occurred in 16 female and four male patients who were 14-70 years old (median, 36 years). Most lesions were situated in the subcutis, superficial muscular fascia, or skeletal muscle of the limbs and limb girdles (15), trunk (3), and the head and neck (2). They were 1.5-11 cm in size (median, 4 cm) and usually described as yellow (13 of 15) and encapsulated (13 of 15). Microscopically they were well circumscribed and consisted of nests, strands, and sheets of eosinophilic and vacuolated cells, which contained glycogen and fat droplets, resembling brown fat cells, lipoblasts and chondroblasts. In all cases there was a variable background of mature adipose tissue associated with a prominent, partially fibrinous to hyalinized myxoid matrix that contained acid mucopolysaccharides usually resistant to hyaluronidase digestion. Several cases had foci of serous atrophy, perivascular fibrosis, and small thrombi; two were focally calcified. The lesions stained for S100 protein (11 of 12), vimentin (10 of 11), and CD68 antigen with KP1 (9 of 11); focal staining for keratin was also seen (4 of 11), but none stained for epithelial membrane antigen or actin or with HMB45. Follow-up in 12 cases (median, 9.5 years) revealed no local recurrences or metastases. Despite its deep location and atypical cellular features, the lesion's nonaggressive behavior suggests it is benign and neither a myxoid liposarcoma nor a myxoid chondrosarcoma, with which it is most frequently confused. The presence of glycogen in vacuolated fat cells is similar to brown fat, and the presence of sulfated stromal mucins supports focal chondroid differentiation. Although the pathogenesis remains uncertain, a lipoma with hibernomatous features, myxoid change, chondroid metaplasia, and secondary degenerative features is favored over a lipogranulomatous process.

Massive crystal deposition is rare in lymphoplasmacytic (LPc) or plasma cell neoplasms. We report three cases in which the accumulation of crystals in histiocytes closely reproduced the histologic features of adult rhabdomyoma. The patients, all female, aged 18, 77, and 78 years, presented with tumor of cervical lymph nodes (two cases) or the otolaryngic mucosa (two cases). In addition, two patients had monoclonal serum or urine immunoglobulin (IgM-kappa-1, unknown-1), and one had renal and bone marrow involvement on biopsy. This last patient died of acute renal failure at 5 months, another was alive without disease at 8 years, and the remaining one was lost to follow-up. Lymph nodes, mucosae, and kidney showed a neoplastic LPc infiltrate masked by sheets of large benign histiocytes containing sheaves of crystals. Paraffin-section immunohistochemistry demonstrated monoclonal staining of the LPc cells in all cases (IgM-kappa-2, IgA-kappa-1) and of the crystals (IgM-kappa) in one case. In all patients, the crystal-containing cells were positive for KP-1 (CD68), but not for desmin, muscle-specific actin, or myoglobin. These findings suggest that, in any case of adult rhabdomyoma in which the histologic findings are not typical, a crystal-storing histiocytosis should be ruled out: recognition of the atypical LPc component and the histiocytic immunophenotype of the crystal-storing cells will help prevent a serious misdiagnosis.

We studied the clinical and pathologic features of 78 malignant peripheral nerve sheath tumors in children less than or equal to 15 years of age. There were 42 boys and 36 girls, with a median age of 10 years. The majority of the tumors (42, or 54%) were central or axial in location; the rest were peripheral. Sixteen patients (21%) had a history of von Recklinghausen's disease. Fourteen (18%) had a malignant peripheral nerve sheath tumor arising in a nerve trunk or a neurofibroma and were unassociated with von Recklinghausen's disease. Patients typically presented with a painful mass of variable duration. Tumors ranged from 2 to 33 cm (median, 7.5 cm) and demonstrated a wide histologic spectrum that included spindled, epithelioid, and primitive neuroepithelial-like cells as well as heterologous elements (11). Immunohistochemical staining revealed S-100 protein in 28 of 50 cases (56%) as well as vimentin (13 of 21 cases, or 62%), Leu 7 (22 of 49 cases, or 45%), actin (eight of 20 cases, or 40%), and keratin (seven of 27 cases, or 26%). Survival status was known for 57 patients (73%). Kaplan-Meier estimates revealed a median survival of 45 months. Half of the patients had local recurrences at 12 months, and half had metastases at 24 months, most commonly to lungs, followed by lymph nodes, liver, bone, soft tissue, and brain. Age greater than or equal to 7 years, male sex, presence of von Recklinghausen's disease, central location, larger tumor size, and tumors with greater than or equal to 25% necrosis were found to be potentially significant adverse prognostic indicators by univariate analysis. Multivariate analysis revealed that larger tumor size, age greater than or equal to 7 years, tumor necrosis greater than or equal to 25%, and von Recklinghausen's disease to be independent adverse prognostic factors.

We report 28 cases of atypical decubital fibroplasia, a distinctive pseudosarcomatous fibroblastic proliferation occurring primarily but not exclusively in physically debilitated or immobilized patients. The subjects included 16 women and 12 men ranging in age from 15 to 95 years. Peak incidence was in the 8th and 9th decades of life. Anatomic locations included the soft tissues overlying the shoulder (eight cases), posterior chest wall (five cases), sacrum (five cases), greater trochanter (four cases), buttock (two cases), thigh (two cases), and arm (two cases). Symptoms were due to a painless mass of 3 weeks' to 6 months' duration. Most lesions were ill-defined, focally myxoid masses that ranged from 1 to 8 cm. Histologically, they were situated in the deep subcutis and secondarily involved adjacent skeletal muscle (11 cases) and tendon (three cases). Extensive epidermal ulceration was typically absent. Microscopically, the lesions had a lobular configuration. They were characterized by zones of fibrinoid necrosis and a prominent myxoid stroma rimmed by ingrowing, ectatic, thin-walled vascular channels. All cases contained atypical, enlarged, degenerated fibroblasts with abundant basophilic cytoplasm, large hyperchromatic, smudged nuclei, and prominent nucleoli; these features resulted in a superficial resemblance to proliferative fasciitis. The enlarged, atypical fibroblasts stained diffusely and strongly for vimentin (15 of 15 cases) and focally for muscle-specific actin (10 of 15 cases), keratin (one of 15 cases), CD68 (10 of 15 cases), and CD34 (five of nine cases) antigens; none of the cases stained for desmin. A malignant diagnosis was considered in 43% of cases. Follow-up in 21 patients ranged from 2 to 78 months (median, 12 months). Two lesions recurred once, one recurred twice, and none metastasized; no deaths were attributable to the lesions. The clinical, histologic, and immunohistochemical features of atypical decubital fibroplasia indicate it is a unique type of pressure sore displaying degenerative and regenerative features distinct from decubitus ulcer. Its recognition by pathologists and clinicians in elderly and debilitated patients is important to avoid misdiagnosis as a sarcoma and to prevent or minimize the occurrence of decubital fibroplasia in progressively aging patient populations.

We describe 65 cases of juxta-articular myxoma (JAM) that occurred in the vicinity of large joints, possessed histologic features of a myxoma, and were frequently associated with cystic changes that resembled a ganglion cyst. The vast majority of cases (57, 88%) occurred in the region of the knee; a minority involved the shoulder (three cases), elbow (three), ankle (one), and hip (one) regions. Patients' ages ranged from 16 to 83 years (median, 43 years; mean, 44 years) and nearly three fourths of the patients (72%) were male. Thirty-seven lesions presented as a swelling or mass, 21 were associated with pain or tenderness, and sizes ranged from 0.6 to 12 cm (median, 3.5 cm; mean, 3.8 cm). Duration of symptoms was highly variable, spanning from 1 week to 18 years. Fourteen JAMs were intimately associated with the meniscus and five of these had a concomitant tear; in five other cases JAM was an incidental finding at the time of total knee or hip arthroplasty for severe osteoarthritis. Of 29 cases with follow-up, 10 (34%) recurred: five recurred once, two recurred twice, two recurred three times, and one recurred four times. While the majority of JAMs were correctly diagnosed as benign, a sarcoma was seriously considered or diagnosed in 15 (23%) cases.

Eleven cases of proliferative fasciitis and myositis in children, ages 2.5 months to 13 years, are presented. Eight lesions averaging 2.3 cm in size occurred in the extremities, two in the head and neck region and one on the chest wall. Like proliferative fasciitis and myositis in adults, these lesions consisted of admixtures of large polygonal to spindled, ganglion-cell-like fibroblasts with vesicular nuclei and prominent inclusion-like nucleoli. Seven of 11 lesions were initially diagnosed as sarcomas, most commonly rhabdomyosarcoma. Four patients were treated by wide excision (three with regional lymphadenectomy), three received chemotherapy, and one was given radiation therapy. There were some histologic differences from adult-type proliferative fasciitis and myositis. The childhood lesions were generally well circumscribed, lobulated, extremely cellular with less collagen production, and often associated with acute inflammation and microscopic foci of necrosis. Immunohistochemical comparison with adult proliferative fasciitis and myositis showed similar immuneprofiles; the ganglion-like cells stained for vimentin and actin and focally with KP1, suggesting myofibroblastic and histiocytic features. None of the lesions stained for keratin, desmin, or S-100 protein. Ultrastructural examination of two cases revealed cells with a constellation of fibroblastic, myofibroblastic, and histiocytic features. Follow-up of seven patients, averaging 58 months from diagnosis, confirmed that all are alive and well. Recognition of this cellular variant of proliferative fasciitis and myositis is important to prevent misdiagnosis as a sarcoma and unnecessary, excessive therapy.

We report 38 cases of inflammatory fibrosarcoma occurring in 23 females and 15 males, 2 months to 74 years of age (median, 8.5 years; mean, 15 years) with symptoms of abdominal pain (17 cases), anemia (21 cases), fever (14 cases), mass (16 cases), and gastrointestinal obstruction (7 cases). Primary tumor sites included mesentery and retroperitoneum (31 cases), omentum (two cases), mediastinum (two cases), liver (one case), diaphragm (one case), and abdominal wall (one case). Sizes ranged from 2.4 cm to 20 cm (mean, 9.6 cm). Follow-up data in 27 cases revealed local recurrences in 10 patients, with multiple local recurrences in three and histologically proven distant metastases to lung (two cases) and brain (one case). Five patients died from their disease (median, 20 months). All tumors, including metastases, consisted of fibroblasts, myofibroblasts, and plasma cells, with variable degrees of fibrosis and calcification. Immunostains indicate myofibroblastic differentiation; 18 of 20 (90%) stained for actin, 15 of 18 (83%) for vimentin, and 10 of 13 (77%) for keratin (primarily in a submesothelial location). Ultrastructural studies also disclosed myofibroblastic features. The locally aggressive, recurrent nature of these neoplasms, as well as the occurrence of metastases and tumor deaths, indicate that they are potentially malignant neoplasms that we believe are better classified as inflammatory fibrosarcomas, not as cellular inflammatory pseudotumors.

Angiosarcoma arising in the central or peripheral nervous system has rarely been reported. Eight patients with primary angiosarcoma of the central nervous system are described here; these included five males and three females ranging in age from 2 weeks to 72 years (mean 38 years). Of the eight neoplasms, six were located in the cerebral hemispheres and one was in the meninges; the site was unknown in the other. All patients underwent surgical resection. Five of the eight patients died, four within 4 months after surgery and one after 30 months. Two of the remaining three patients were 17 and 27 years old at the time of diagnosis and were alive at follow-up review 39 and 102 months after surgery, respectively. One patient was lost to follow-up monitoring. Microscopically, all eight tumors demonstrated a well-differentiated pattern with irregular vascular channels and intraluminal papillae; in addition, four showed poorly differentiated solid areas. Immunohistochemical staining of neoplastic cells to factor VIII-related antigen and Ulex europaeus agglutinin I was performed in five tumors and was focally positive in four. No correlation could be shown between the histological features and the growth and biological behavior of the tumors.

Nine cases of a previously undescribed benign soft tissue tumor are reported. They were composed of variable amounts of benign smooth muscle and mature adipose tissue. Patient ages ranged from 28 to 73 years. One was located in the subcutaneous adipose tissue, one in the rectus sheath of the anterior abdominal wall, two within the abdominal cavity and attached to the abdominal wall, two in the inguinal region, and three in the retroperitoneum. Sizes varied between 3.5 and 26 cm and averaged 16 cm in greatest dimension. Two of the retroperitoneal tumors were incidental findings during other operative procedures. The remaining seven cases were clinically palpable masses. Eight of the nine lesions were originally diagnosed as benign, and another (retroperitoneal) was diagnosed as well-differentiated liposarcoma. Five of the tumors were at least partially encapsulated. In three of the cases, a nonlipomatous component was grossly recognized. Although the benign nature of this lesion is usually recognized in superficial locations, deeply situated tumors are more likely to be confused with a well-differentiated liposarcoma.

Nineteen cases of fibrolipomatous hamartoma of nerve without macrodactyly and seven cases with macrodactyly are discussed. Twenty-five involved the hand, wrist, palm, and finger, and one case involved the foot. Nineteen patients had isolated fibrofatty enlargement of nerve, while seven had macrodactyly in addition to the peripheral nerve changes. Involved nerves included the median nerve, ulnar nerve, an unidentified nerve near the elbow, and a nerve on the dorsum of the foot. Four of nine patients with neurologic symptoms of pain or paresthesias had physical findings compatible with compression neuropathy, and two others were described as having carpal tunnel syndrome. Most patients had been aware of a mass for several years. Microscopically, the lesion was characterized by fibrofatty enlargement of nerve with massive epineural and perineural fibrosis. In two of the cases with macrodactyly, the fibrofatty enlargement of the nerve was associated with overgrowth of bone and the surrounding subcutaneous tissues. In one case, the perineural fibrosis was associated with metaplastic bone. The histogenesis of fibrofatty overgrowth of nerve has been disputed. Mature fat cells have been described within the normal nerve sheath, and it is thought that proliferation of these cells leads to the fatty enlargement of the nerve and its coverings. The relationship of these neural changes to the development of macrodactyly remains controversial. Follow-up in 18 patients (69%) reveals a benign course following biopsy, limited excision, or division of the flexor retinaculum in the wrist.

A unique case of malignant fibrous histiocytoma arising within the thigh of a patient with Type II A (hypercholesterolemic) hyperlipoproteinemia is described. The tumor, which appeared grossly as a benign tuberous xanthoma, demonstrated pleomorphic spindled and multinucleated cells focally in the distinct storiform pattern of a malignant fibrous histiocytoma and areas composed of bland xanthoma cells associated with cholesterol deposits. Foci of xanthoma cells with mildly atypical nuclei admixed with highly pleomorphic cells were also noted. These unusual histologic features--as well as the uniform staining of all the tumor cells with anti-alpha-1-antichymotrypsin and the absence of anti-alpha-1-antitrypsin and of anti-lysozyme staining--support the conclusion that all elements of this malignant tumor were derived from a common mesenchymal precursor. The exaggerated histiocytic capability of the tumor cells in the form of xanthomatous change was probably in response to the hyperlipoproteinemic microenvironment.

Papillary endothelial hyperplasia is a peculiar benign intravascular process that bears a remarkable resemblance to a hemangiosarcoma. In 44 cases of this lesion studied from the files of the Armed Forces Institute of Pathology, the process manifested as a small tumor-like lesion that occurred most frequently in the subcutis of the fingers (14 cases), the head and neck region (ten), and the trunk (seven). Microscopically, the tuft-like or papillary proliferation of endothelial cells was nearly always intimately associated with a thrombus and seemed to represent a peculiar variant of an organizing process. Features that aided in recognition and differential diagnosis from a hemangio-sarcoma included the intraluminal location of the lesion, the absence of tissue necrosis, and the intimate association of the proliferated tuft-like structures with thrombotic material. Follow-up information obtained in 31 cases indicated a benign clinical course despite the sarcoma-like microscopic appearance of this condition.

We report 75 cases of malignant lymphoma presenting in soft tissue taken from the files of the Armed Forces Institute of Pathology. All histologic subtypes with the exception of lymphoblastic lymphoma were represented. Our findings indicate that virtually any soft tissue site may be involved; there is no sex predilection; and size is not helpful in predicting survival. Among the 55 patients for which race was known, there were no black patients. Thirty-three patients with extensive evaluations at the time of diagnosis had no evidence of disseminated disease, but eight of these exhibited widespread disease within 3 months of diagnosis, and seven of the eight died of disease (median survival, 4 months). The remaining 25 patients had much better outcomes; 18 of 19 with intermediate and high-grade lymphomas were alive and well at a median of 74 months after diagnosis. Some tumors exhibited a propensity for involvement of remote soft tissue sites.

The pathologic features and the behavior of 53 cases of infantile fibrosarcoma are presented. The tumor nearly always occurred during the first 2 years of life; 41 of the 53 cases occurred during the first, six during the second, and three each during the third and fourth year of life, respectively. Twenty of the 53 cases were present at birth. The tumor was more common in boys (60%) and affected chiefly the distal portions of the lower and upper extremities (72%). Most of the tumors grew rapidly and reached a large size within a few weeks or months. They were generally poorly circumscribed and infiltrated variously subcutaneous fat, muscle, fascia and tendons. Microscopically, they were composed of immature-appearing spindle-shaped cells and were marked by their high cellularity and prominent mitotic activity. Despite these features, follow-up information revealed a favorable clinical course, particularly as compared with the adult form of fibrosarcoma. Of the 48 patients with follow-up data, 31 were alive and well with no evidence of recurrence, eight were alive with recurrence, and one was alive following lobectomy for metastatic tumor. Of the living patients, 12 were treated with amputation, nine with radical or wide local excision, and 15 with simple excision. In two cases surgery was followed by chemotherapy, and in one, by radiotherapy. Eight of the 48 patients with follow-up had died, four of metastatic tumor (8.3%) and four of miscellaneous causes. Wide local excision appears to be the treatment of choice unless the size of the tumor and its anatomic location require amputation. Since late recurrent and metastatic lesions were encountered, long-term followup is necessary before one can safely assume that the patient has been cured.

A retrospective study of 141 cases of clear cell sarcoma of tendons and aponeuroses revealed that the tumor occurred predominantly in young patients between 15 and 35 years of age, was slightly more common in female than in male patients, and originated chiefly from tendons, aponeuroses, and fascial structures of the extremities with a predilection for the feet and knees. The tumor presented as an insidiously growing mass causing pain or tenderness in slightly more than half of the patients. The preoperative duration of symptoms varied greatly, and in 29 cases the time interval between discovery of the tumor and operation exceeded 5 years. Microscopically, the tumors varied little in appearance and were composed of short fascicles of fusiform cells with a clear to granular eosinophilic cytoplasm, vesicular nuclei with prominent nucleoli, and occasional multinucleated giant cells. Melanin was demonstrated in 72% of the 92 tumors in which the Fontana or Warthin-Starry preparation for melanin was performed. S-100 protein, a neuroectodermal marker, was positive in 13 of 19 cases. Follow-up information was available in 115 patients. Thirty-four (29.6%) were alive and well with no evidence of recurrence. Twenty-four (20.9%) patients were alive with one or two recurrences, three (2.6%) were alive following pulmonary lobectomy for metastatic sarcoma, and one was alive with metastasis in the thoracic spine. Fifty-three of the 115 patients with follow-up information had died, 50 from metastatic tumor and three from miscellaneous causes. The prevailing sites of metastasis were the lung and the regional lymph nodes. The exact histogenesis remains obscure, but the presence of intracellular melanin in two-thirds of the cases supports origin from migrated neural crest cells with the capacity for producing melanin. For this reason the term, malignant melanoma of soft parts, seems preferable over the purely descriptive term of clear cell sarcoma.

The clinical and pathologic features of 61 cases of congenital and infantile myofibromatosis are presented. The tumor affected almost exclusively infants and young children; 88% of cases occurred before the age of two years, and 60% were noted at birth or shortly thereafter. Solitary (45 cases) and multicentric (16 cases) forms of the tumor could be distinguished; the solitary form was more common in males (69%) and affected chiefly the soft tissues of the head-neck region and the trunk. The multicentric form, on the other hand, predominated in females (63%) and was found not only in soft tissues but also in bones and viscera. Fourteen of the 16 cases with multicentric lesions were present at birth, and four of them had evidence of visceral involvement. Among the 16 cases were two sets of siblings, both brother and sister. Grossly, nearly all of the tumors were well demarcated; they measured from 0.5 to 7 cm in greatest diameter. Microscopically, they formed well-circumscribed nodules consisting of short bundles of plump, spindle-shaped cells displaying staining characteristics intermediate between fibroblasts and smooth muscle cells. Necrosis or a hemangiopericytoma-like pattern was often found in the center of the tumor nodules. Intravascular growth was encountered in several instances, but this feature did not seem to affect the clinical behavior. Of the 43 patients with follow-up data (mean-follow up 5.1 years), 36 were alive and well. Of the solitary lesions, three recurred. Of the multicentric lesions, five of the 15 patients showed evidence of spontaneous regression of both soft tissue and bone lesions. Four died, three of extensive involvement of multiple viscera, especially the lung, and one of "crib-death."

This article describes 41 examples of an unusual fibrohistiocytic sarcoma which occurred primarily in the extremities of young individuals between the ages of 5 and 25 years (median 13 years). It manifested as a nodular subcutaneous growth that seldom caused tenderness or pain, and clinically was often mistaken for a hematoma or a hemangioma. Grossly, the tumor presented as a circumscribed, multinodular or multicystic, hemorrhagic mass that ranged in size from 0.7 to 10 cm (median 2.5 cm). On microscopic examination, it consisted principally of 1) solid arrays or nests of fibroblast- and histiocyte-like cells, not infrequently containing varying amounts of intracellular hemosiderin or lipid, 2) focal areas of hemorrhage or hemorrhagic cyst-like spaces, sometimes occupying the major portion of the tumor, and 3) aggregates of chronic inflammatory cells, chiefly lymphocytes and plasmacytes, a feature that caused confusion with a lymph node metastasis in several cases. Follow-up information, available in 24 patients, revealed a variable clinical course. Twenty-one patients were alive, 11 with recurrence (including one with 9 recurrences in a 21-year period) one with recurrence and metastasis and one with metastasis. Three patients had died of metastasis 1, 3, and 13 years respectively, after the initial surgical therapy. The exact histogenesis is still obscure. Most likely it is a tumor of fibroblast- and histiocyte-like cells, akin to malignant fibrous histiocytoma, but different in its age incidence, microscopic appearance and behavior.

The clinical and pathologic features of 53 cases of proliferative fasciitis, a pseudosarcomatous process involving fascia and interlobular fibrous septa of the subcutaneous fat, were reviewed. In the reviewed material, the lesion affected adults exclusively, with a high incidence in patients older than 40 years (median 54 years). It involved most commonly the upper and lower extremities, and microscopically was characterized by a diffuse infiltrative fibroblastic growth intimately associated with multifocal proliferation of large basophilic cells, closely resembling ganglion cells--a microscopic picture akin to proliferative myositis. In 16 of the 53 cases, the lesion had been initially confused with sarcoma because of its rapid growth and its bizarre histologic features. Although the term "proliferative fasciitis" has been used in the past as a symptom for nodular fasciitis, it is suggested that it be limited to the lesion under discussion, in order to emphasize its close relationship to proliferative myositis. Followup information revealed a benign clinical course. Therefore, despite its rapid growth and bizarre microscopic appearance, the lesion is adequately treated by local excision, and there is no indication for radical surgery.

We describe 59 cases of a microscopically unique neoplasm that has not been previously reported. The tumor almost exclusively affected adults (range 14-79 years) and had a male predominance (38 men and 21 women). It presented in most cases as a small, painless, well-circumscribed mass (median, 4 cm) in subcutis or muscle. It occurred chiefly in the upper and lower extremities (40 cases) and less frequently in the trunk (11 cases) and the head and neck region (eight cases). Microscopically, the tumor was partly lobulated and composed of small, round cells that had vesicular nuclei and indistinct cytoplasm. Typically, the cells were arranged in a cord- or nestlike pattern within a myxoid matrix that frequently showed transitions toward hyaline fibrosis and focal osteoid formation. In about two-thirds of the cases, the cells contained immunoreactive S-100 protein. An additional typical feature, seen in 48 (81%) of the 59 cases, was the presence of an incomplete shell of mature bone in the capsular region of the tumor. Follow-up information, available in 41 cases, revealed that 11 patients (27%) experienced one or more recurrences. One patient with three recurrences developed a second tumor in the opposite thigh, presumably a metastasis. None of the patients died of the tumor, but three died of causes unrelated to the disease. Although the histogenesis is uncertain, cartilaginous or neural origin seem to be most likely. Until this issue is resolved, we prefer the descriptive and less committal designation of "ossifying fibromyxoid tumor of soft parts."

A case-control study was conducted in men who were of draftable age during the Vietnam conflict to examine the association of soft tissue sarcomas (STSs) with military service in Vietnam as well as other host and environmental risk factors. A total of 217 STS cases selected from the Armed Forces Institute of Pathology were compared to 599 controls for Vietnam service, occupational and nonoccupational exposure to various chemicals, occupational history, medical history, and life-style (smoking, alcohol, coffee, etc.). Military service information was verified by a review of the patient's military personnel records. Other information was ascertained from a telephone interview with either subjects or their next of kin. Cases and controls were stratified on the basis of the hospital type (civilian, Veterans Administration, and military); the Mantel-Haenszel estimate of the odds ratio (OR), adjusted for the effects of the stratification variable, was calculated. Vietnam veterans in general did not have an increased risk of STS when compared to those men who had never been in Vietnam (OR, 0.85; 95% confidence interval, 0.54-1.36). Subgroups of Vietnam veterans who had higher estimated opportunities for Agent Orange exposure seemed to be at greater risk of STSs when their counterparts in Vietnam were taken as a reference group. However, this risk was not statistically significant.

Seventeen cases of intravascular fasciitis were reported from the files of the AFIP (14 cases) and the Pathology Department, Thomas Jefferson University Hospital (three cases). It is characterized by the histologic features of nodular fasciitis but with intraluminal, intramural, and extramural involvement of small to medium-sized veins and arteries and multinodular or serpentine growth along the course of affected blood vessels. A painless, slowly growing mass was most common. Fourteen patients (82%) were under age 30 (range 1/2-57 years); the sex ratio was about equal. Seven cases were located in the upper extremity (three hand, two wrist or forearm, two shoulder), three on the ankle or lower leg, five on the head and neck, and two in the chest wall and breast. Most cases were small with a mean diameter of 1.5 cm, but two were elongated masses measuring 4-5 cm in length. At surgery, four cases showed intimate association with large veins or arteries. This type of fasciitis is rare and has been found in only one of 14 consecutive cases of modular fasciitis operated at this university hospital between 1969 and 1978. Six of 15 consultation cases were originally confused with sarcoma. Intravascular fasciitis is benign. Seven patients were free of disease from 2.5 to 20 years (mean 9.5 years); two patients had local recurrences.

We report 65 cases of a hitherto undescribed neoplasm that occurs chiefly in children and young adults, and has morphologic features reminiscent of both a fibrous histiocytoma and fibromatosis. The median age of the 65 patients was 14.5 years; two-thirds (67.7%) of the patients were younger than 20 years. The lesion was more common in female patients (46 cases) than in male patients (19 cases). It usually presented as a slow-growing, poorly demarcated dermal or subcutaneous mass that rarely exceeded 3 cm in greatest diameter. Its most common location was the upper extremity (63.1%), especially the regions of shoulder and forearm. Under the microscope, the lesions were characterized by a multinodular or plexiform proliferation of histiocyte- and fibroblast-like cells associated with multinuclear giant cells. Differential diagnosis chiefly includes cutaneous fibrous histiocytoma, plexiform neurofibroma, fibromatosis, and benign and malignant giant cell tumor. Twenty of the 32 cases (62.5%) with follow-up information were alive and well after local excision, but the tumor recurred in 12 cases (37.5%). In two patients with recurrence, the disease metastasized to regional lymph nodes 9 and 36 months after the initial excision, respectively. Metastasis to the lung or other organs was not observed. We were unable to demonstrate a close correlation between biologic behavior and any specific clinical or morphologic parameter.

A retrospective study of 88 cases of extraskeletal osteosarcoma revealed that this tumor affects adults almost exclusively, with a high incidence in patients older than 50 years, and is slightly more common in males (58%) than in female patients. The tumor occurred principally as a soft tissue mass in an extremity, with a predilection for the thighs (lower extremity, 46.6%; upper extremity, 20.5%) and the retroperitoneum (17%). Most were deep-seated and were firmly attached to the fascia, but occasionally they were freely movable and confined to the subcutis or dermis. Nearly all presented as an insidiously growing mass rarely causing pain or tenderness. The preoperative duration of symptoms ranged from 2 weeks to 25 years (median, 6 months). In 17 cases, it exceeded 2 years. A history of prior trauma to the site of the tumor was stated in 11 of the 88 cases (12.5%) and of radiation in five cases (5.7%). Microscopically, the tumors contained varying amounts of neoplastic osteoid and bone, sometimes together with islands of malignant-appearing cartilage. Like osteosarcoma of bone, extraskeletal osteosarcoma showed a striking variation in histologic appearance and focally resembled malignant fibrous histiocytoma, fibrosarcoma, and malignant schwannoma. Follow-up information was available for 65 patients. Eight (12.3%) patients were alive with no evidence of recurrence; 12 (18.5%) patients were alive with one or more recurrences; and five (7.6%) were alive with metastases. Twenty-eight of the tumors (43%) recurred and 39 (63%) metastasized. Forty (61.5%) of the patients with follow-up information had died, 36 from the tumor and four from miscellaneous causes. The prevailing sites of metastases were the lung, the regional lymph nodes, and bone.

Two infants with benign, hamartomatous tumors composed of well-differentiated and intimately admixed neural and striated muscle components are presented. Their histogenesis is discussed in light of embryologic concepts of the derivation of mesenchymal tissues from neuroectoderm and in reference to previous reports of benign and malignant tumors of the nervous system with striated muscle components.

Intermediate-sized filaments have been noted in epithelioid sarcoma by previous investigators, two of whom have reported that the filaments represent vimentin. We utilized polyclonal antibodies directed against keratin and immunoperoxidase techniques (PAP) to stain 32 of the more than 300 cases accumulated at the AFIP . All of our material was formalin-fixed, paraffin-embedded. Seventy-five percent of our cases (24/32) showed positive immunoreactivity, a feature that may be of diagnostic help in distinguishing epithelioid sarcoma from modular fasciitis, benign and malignant fibrous histiocytoma, malignant melanoma, and necrotizing granuloma. In these cases, the reaction was enhanced using predigestion with trypsin. The immunoreactivity varied from tumor to tumor, perhaps due to formalin fixation. Since synovial sarcoma and mesothelioma may also be cytokeratin-positive, our findings indicate that keratin immunoreactivity is not confined to epithelial tumors and may also occur in neoplasms traditionally regarded as mesenchymal.

The clinical and pathologic findings of 28 examples of fibromatosis of the breast not involving the deep fascia or chest wall are reported. Five of the 20 lesions treated by local excision recurred. Recurrences developed within a 4 to 8 month period following surgery in four of the five instances, and 6 years after surgery in one instance. One lesion recurred five times over a period of 3 years. None of the patients died from their disease, and none developed a metastasis. Those lesions that recurred had been inadequately excised initially, since surgical margins showed fibromatosis. Specific histological features, such as size, cellularity, atypia, and mitotic figures, were not helpful in predicting recurrence. Although local excision appears to have been adequate in the majority (75%) of the patients, the infiltrative nature of fibromatosis necessitates documentation of tissue margins in order to avoid the possibility of recurrence. The differential diagnosis includes benign reactive processes (such as keloid and nodular fasciitis), fibrous histiocytoma, low-grade spindle-cell (metaplastic) carcinoma, and fibrosarcoma.

A retrospective review of 241 cases of epithelioid sarcoma reaffirmed the propensity of this tumor to occur in the distal extremities of young adults. The tumor was generally firm and nontender, and involved the dermis, subcutis or deeper soft tissues, particularly fascial planes, aponeuroses, and tendon sheaths. Follow-up data, available in 202 cases (84%), showed a 77% recurrence and a 45% metastatic rate. The most common initial sites of metastasis were lymph nodes (48%) and lungs (25%). A more aggressive course was associated with a proximal or axial tumor location, increased size and depth, hemorrhage, mitotic figures, necrosis, or the presence of vascular invasion. More favorable behavior was observed when the tumor arose in younger individuals, in distal extremities, or in females between the ages of 10 and 49. (The last observation calls for further work with steroid receptors.) Radical excision or amputation still appears to be the initial treatment of choice, though adjunctive high-dose radiotherapy to the excision site may prove to be of additional value.

This article reviews the clinicopathologic features and the biological behavior of 24 cases of synovial sarcoma that took origin from the cervical prevertebral connective tissue space and manifested as a retropharyngeal tumor or as a palpable mass in the anterior or posterior cervical triangle. The age of the 24 patients ranged from 10 to 51 years, with a median of 19 years. Ten patients were women and 14 men. Hoarseness or difficulty in breathing or swallowing were the first symptoms in eight patients. The tumors were solitary and ranged from 2 to 10 cm in greatest dimension. Microscopically, all of the cases showed the characteristic biphasic cellular pattern of a synovial sarcoma, with epithelioid and fibrosarcoma-like areas in varying proportions. Synovioblastic origin of the neoplasm was confirmed by the results of histochemical staining procedures and, in 1 case, by the examination with the electron microscope. Of the 21 cases followup information, 12 had died (10 with pulmonary metastasis) and 9 were alive and free of symptoms. Prompt and complete surgical removal is required to prevent complications from recurrent tumor growth or metastasis.

The clinical and pathological features of 104 cases of chondroma of soft parts are presented. The tumor occurred predominately in the third and fourth decades, was slightly more common in male (61%) than in female patients, and affected chiefly the soft tissues of the hand (64%) and feet (20%). The presenting symptom was usually a slowly and insidiously growing mass, occasionally causing tenderness or pain. Nearly always the tumor was well demarcated and lobulated and measured between 1 and 2 cm in greatest diameter. Microscopically, most of the tumors were composed of adult-type hyaline cartilage, undergoing calcification in a large percentage of cases. In addition, histologic variants with giant cell proliferation and chondroblastic activity could be distinguished. Despite the slight cellular pleomorphism and the plump appearance of many cartilage cells in the chondroblastic variants, there was no evidence that these tumors behaved differently from the tumors composed predominately of adult-type hyaline cartilage. Of the 56 patients with follow-up information (median follow-up period, 5.7 years) 44 were alive and well with no evidence of recurrence in the follow-up period. In 10 patients the tumor had recurred once. Multiple recurrences or metastatic lesions were no observed. Two patients died of unrelated cause. Complete local excision appears to be the treatment of choice.

A clinicopathologic study of 48 cases of pleomorphic lipoma from the files of the Armed Forces Institute of Pathology reveals that this tumor occurs principally in males (83%) in the fifth to seventh decades (mean 57 years) and shows a predilection for the posterior neck, shoulder, and back. Typically, the lesion appears as a painless, circumscribed subcutaneous mass that, on gross examination, resembles an ordinary lipoma. However, microscopically, in contrast to the uniform appearance of the mature adipose tissue cells of an ordinary lipoma, this neoplasm is characterized by an intimate admixture of variably-sized fat cells, and bizarre, pleomorphic, multinucleated giant cells. Many of the latter cells show a distinctive floret-like arrangement of the nuclei and are associated with interlacing bundles of dense birefringent collagen. Despite this pleomorphic picture, which not infrequently leads to a misdiagnosis of liposarcoma, follow-up data obtained for 34 patients (median follow-up period of three years) establish the invariably benign clinical behavior of this unusual tumor.

A series of 106 cases of hemangiopericytoma was analyzed. The neoplasms occurred principally in adults (median age, 45 years), were deep seated, and were most common in the thigh (27 cases) and the pelvic retroperitoneum (26 cases). A painless mass was the first symptom in 96 of the patients. The median size of the excised tumors was 6.5 cm. Surgical removal of the tumor was often complicated by hemorrhage because of marked dilatation of the vascular bed in the vicinity of the neoplasm, probably as the result of rapid exchange of blood from the arterial to the venous circulation within the tumor. Microscopically, benign and malignant forms could be distinguished. The latter were characterized by increased cellularity, prominent mitotic activity, and foci of necrosis or hemorrhage. Follow-up information was obtained in 93 cases. Seventy-one of the 93 patients were living (two with recurrence and four with metastasis), and 22 had died (13 as the result of recurrence or metastasis in more than two-thirds of the related causes). Recurrence preceded metastasis in more than two-thirds of the patients with evidence of metastasis. The 10 year survival rate was 70 per cent. The morphologic differences from other mesenchymal tumors showing a hemangiopericytoma-like vascular pattern are discussed, and the close resemblance of hemangiopericytoma to richly vascular forms of fibrous histiocytomas and synovial sarcoma is emphasized. Congenital or infantile hemangiopericytoma is described as a separate entity having a distinctive microscopic pattern and behavior.

Thirty-three histologically diverse bone and soft tissue tumors were analyzed biochemically for the presence of estrogen receptor protein (ERP) and progesterone receptor by means of a conventional, commercially available, steroid-binding assay (dextran-coated charcoal method) on fresh frozen tissue. These results were compared with analysis of ERP by using a specific monoclonal antibody both in an enzyme immunoassay and on frozen tissue sections by using immunohistochemical procedures. Frozen tissue sections were also examined for the presence of estrogen and progesterone receptors using fluorescein-labeled steroids. Six of the 33 tumors (18%) contained low levels of ERP ranging from 19 to 73 fmol/mg as determined by the dextran-coated charcoal method. The remaining 27 cases contained no (less than 10 fmol/mg) ERP. The ERP-positive group included a fibromatosis, leiomyosarcoma, liposarcoma (2 cases), neural sarcoma, and a synovial sarcoma. Four were high grades sarcomas, and two were low grade sarcomas. There was excellent agreement between the ERP levels determined by the dextran coated charcoal method and those determined by enzyme immunoassay. ERP could not be demonstrated immunohistochemically on frozen tissue sections of the tumors even though it could be demonstrated in breast carcinomas serving as positive controls. The failure of the immunohistochemical technique may be related to the low levels of ERP in these tumors and the difficulty of detecting antigen at threshold levels. Cytochemical localization of receptor protein employing fluoresceinated steroids did not correlate with cytosolic ERP as determined by enzyme immunoassay or the dextran coated charcoal method. Moreover, the high level of background fluorescence gave rise to a significant amount of intraobserver and interobserver variation. Although the clinical significance of ERP protein in mesenchymal tumors is still uncertain, the present findings, coupled with various clinical observations suggesting hormonal dependency of some mesenchymal tumors, indicate that investigation of a larger group of patients amenable to statistical analysis is warranted.

Epithelioid hemangioendothelioma (EH) is the prototype of a group of vascular tumors characterized by an epithelioid or histiocytoid endothelial cell. This family also includes the epithelioid hemangioma (angiolymphoid hyperplasia with eosinophilia) and epithelioid forms of angiosarcoma. This review discusses the principal clinical, pathologic, and biologic differences among these three lesions. In particular the various manifestations of EH of soft tissue, bone, lung (previously called intravascular bronchioloalveolar tumor), and liver are discussed. Long-term follow-up data of EH of soft tissue and lung are provided.

Two hundred and two benign and malignant soft tissue lesions were studied for the presence of S-100 protein by means of the peroxidase-antiperoxidase technique on formalin-fixed, paraffin-embedded tissue. Virtually all benign nerve sheath tumors (neurofibroma, neurilemoma, and granular cell tumor) contained numerous immunoreactive S-100-positive cells. Only one-half (18 of 36) of malignant schwannomas contained the protein, suggesting that its presence is an expression of differentiation in Schwann cell tumors. S-100 protein was not identified within pure neuroblastic tumors (neuroblastoma, neuroepithelioma) but could be identified within rare cells of the ganglioneuroblastoma and within the Schwann cell component of ganglioneuroma. It was also identified within most melanocytic tumors (cellular blue nevus, clear cell sarcoma, and melanoma). In fact, its constant presence in melanoma indicates that it may prove to be an independently reliable method for diagnosing amelanotic forms. It is also sporadically present within a variety of mesenchymal lesions including lipoma, liposarcoma, synovial chondromatosis, chondrosarcoma, fibromatosis, histiocytosis X, and chordoma. Although S-100 protein is highly characteristic of neural crest-derived tumors, it is not restricted to them and, consequently, must be interpreted cautiously. It may prove helpful in select situations such as the distinction of (a) benign nerve sheath tumors from other benign mesenchymal tumors such as fibrous histiocytomas, (b) cellular neurilemomas from malignant schwannomas, (c) malignant schwannomas from conventional fibrosarcoma (d) malignant melanomas from many carcinomas, and, possibly (e) juvenile xanthogranulomas from histiocytosis X.

The clinicopathologic findings in 200 cases of malignant fibrous histiocytoma (MFH) with follow-up information are presented. This tumor occurred principally as a mass on an extremity (lower extremity 49%, upper extremity 19%) or in the abdominal cavity or retroperitoneum (16%) of adults (peak incidence 61-70 years of age). It typically involved deep fascia (19%) or skeletal muscle (59%) and only rarely was confined to the subcutis without fascial involvement (7%). The MFH had variable morphologic features and frequently showed transitions from areas having a highly ordered storiform pattern to less differentiated areas having a pleomorphic appearance. The rate of local recurrence of the tumor was 44%, and of metastasis, 42%. Metastasis was most frequently to the lung (82%) and lymph nodes (32%). Factors that influenced the rate of metastasis included depth, size, and inflammatory component of the tumor. Tumors that were small, superficially located, or had a prominent inflammatory component metastasized less frequently than larger, more deeply located tumors. In our experience the MFH is the most common soft tissue sarcoma of late adult life, and many tumors previously diagnosed as pleomorphic variants of liposarcoma, fibrosarcoma, or rhabdomyosarcoma are probably examples of MFH. Although the histogenesis of this neoplasm remains controversial, we feel it is best regarded as a primitive and pleomorphic sarcoma showing partial fibroblastic and histiocytic differentiation, as reflected by collagen production and occasional phagocytosis.

Infantile myofibromatosis is a distinct clinicalpathologic entity occurring primarily in neonates and infants either as a single nodular lesion or as a multicentric form. We have recently studied two cases of this disorder in neonates, and a third involving the father of one of these infants, all documented by biopsy. Evidence in support of an autosomal-dominant mode of inheritance for infantile myofibromatosis and of its potential to recur after a long period of quiescence is presented.

Twenty-six cases of a newly recognized form of vascular tumor are presented. The tumor may occur at any age, has a male predominance, and develops preferentially in the dermis and subcutaneous tissues of the distal extremities. Histologically it combines the features of both a cavernous hemangioma and Kaposi's sarcoma. It is composed of thin-walled cavernous vessels which may be dilated, partially collapsed, or filled with organizing thrombi and phleboliths. These areas are intimately associated with spindled areas reminiscent of Kaposi's sarcoma. The spindled areas differ from Kaposi's sarcoma by the presence of occasional epithelioid endothelial cells, which sometimes display vacuolization. Follow-up information in 14 cases indicates that nine patients experienced "recurrences." One patient, who also received radiotherapy, developed regional lymph node metastasis 40 years after diagnosis and following 19 recurrences. No patient, however, has died of his disease, despite relatively limited surgical excision. The term "spindle cell hemangioendothelioma" is suggested for this vascular tumor of low-grade malignancy.

Synovial sarcoma arises most commonly in the lower extremity, particularly in the region of the lower thigh and knee. Yet the occurrence of thus mesenchymal neoplasm in the head and neck area has been convincingly documented, albeit confined almost exclusively to cervical and parapharyngeal sites. Therefore, in view of its rarity in the head and neck, we analyzed a group of 11 synovial sarcomas arising in the orofacial region. The series comprised nine men (82%) and two women (18%). In common with synovial sarcoma at more conventional sites, this is a disease of young adults: ages ranged from 16-49 years (median, 34 years). Topographically, two subsets were delineated, a more common facial group with eight cases (four cheek, two parotid region, one infraorbital, one submental), all arising as gradually enlarging, usually nontender, solitary tumors; and three intraoral ones (two tonsillar, one lingual), two of which were polypoid and one was an exophytic tonsillar mass which presented with hemoptysis and stridor. Follow-up data, obtained for nine patients (range, 1.3-15.0 years), disclosed three (33%) tumor-related deaths, all belonging to the facial group. Treatment, difficult to significantly correlate with survival in this small series, varied from surgical excision alone to a multimodality approach including both irradiation and chemotherapy. Histologically, all the neoplasms revealed characteristic biphasic features, predominantly fibrosarcomatous in one, but, more typically, showing epithelial clefts and/or pseudoacinar spaces in the others. Differential diagnosis, depending on the proportion of the biphasic components, ranged from spindle cell mesenchymal neoplasms to various adenocarcinomas, including those arising in mixed tumors of salivary gland.

A clinicopathologic analysis of 28 cases of giant cell fibroblastoma (GCF), a rare mesenchymal tumor occurring predominantly in the first decade of life, is presented. This disease presented as a painless, slowly enlarging, subcutaneous mass. The tumor recurred locally in 47% of the patients; however, metastasis was not detected. On microscopic examination, GCF showed an unique combination of spindle cell patterns, pleomorphic and multinucleated giant cells, myxoid areas, and distinctive sinusoid-like spaces. This unrecognized histomorphologic picture led to a misdiagnosis of sarcoma in 40% of the cases. The histogenesis of this lesion remains uncertain; however, based on both clinical and morphologic similarities, it is proposed that GCF is a juvenile form of dermatofibrosarcoma protuberans (DFSP).

This article reviews the pathologic features and the behavior of 39 small, round, or oval cell sarcomas occurring in the soft tissues and considered histologically indistinguishable from Ewing's sarcoma of bone. The tumors affected chiefly young adults (median age 20 years) and most commonly involved the soft tissues of the lower extremity and the paravertebral region. Microscopically, they consisted of solidly packed small, round, or ovoid cells of great uniformity, arranged in sheets or lobules separated by strands of fibrous connective tissue. The nucleus of the tumor cells contained finely divided chromatin, a distinct nuclear membrane, and frequently a minute nucleolus. The scanty ill-defined cytoplasm contained varying amounts of glycogen. Sometimes the histologic picture was dominated by a "peritheliomatous" pattern, or by large areas of necrosis or hemorrhage. Followup data ranging from 1 month to 14 years were available in 35 of the 39 cases (93%). Of these, 13 were alive and 22 had died. In the majority of the fatal cases, the clinical course was rapid; metastatic lesions developed within a few months after the primary tumor was excised. The lungs and the skeleton were the two most common sites of metastasis. Cure may be achieved by wide local excision of the tumor at an early stage of the disease, combined with radiation therapy and chemotherapy.

The clinicopathologic features of 53 cases of postradiation soft tissue sarcoma (PRS) were correlated with the physical characteristics of the administered radiation. All but three patients received radiation for malignant processes. Of the secondary sarcomas, malignant fibrous histiocytoma (MFH) accounted for 36 cases (68%), followed by seven extraskeletal osteosarcomas (13%), six fibrosarcomas (11%), two malignant Schwannomas (4%), one extraskeletal chondrosarcoma, and one angiosarcoma. The sex incidence, age of the patient at time of diagnosis, and location of the PRS correlated only with the clinical characteristics of the initial treated condition. The latency period (mean 10 years) showed an indefinite relationship to patient survival but no definite relationship to the patient's age at the time of the initial radiation. There was no difference between patients treated with megavoltage radiation (39 patients) and with orthovoltage radiation (seven patients) in the type of sarcoma, location, or survival, although the orthovoltage group received a lower mean radiation dose (3880 rads) than the megavoltage group (4446 rads). Megavoltage radiation, however, produced deeper tissue radiation changes and was associated with a shorter latency period. Most PRS were poorly differentiated, produced abundant collagen, and had a dismal prognosis.

Twenty-one cases of a benign fibro-osseous pseudotumor occurring in the soft tissues of the digits are described. They affected mostly young adults. Twenty of the 21 cases involved the soft tissues of the fingers, especially the proximal portions of the index or middle finger, and one case involved the toe. Microscopically these tumor-like lesions closely resembled myositis ossificans, but unlike this process they involved chiefly the subcutaneous tissue and adjacent fibrous structures and were marked by an irregular multinodular growth pattern without the typical zoning of myositis ossificans. Because of the focal hypercellularity, cellular atypia and increased mitotic activity six of the cases were initially interpreted as being parosteal or extraskeletal osteosarcoma. Follow-up information indicates that this lesion behaves in a nonaggressive fashion and is curable by complete local excision.

Nine cases of fibroblastic lesions occurring in the cranium of young children were reviewed. The age of the patients at the time of initial treatment ranged from three weeks to six years (median 18 months), with the lesions being congenital in two cases. There was 2:1 male predominance. The size of the lesions averaged 2.5 cm in greatest dimension with the largest being 9.0 cm. All cases presented as rapidly growing masses with a preoperative duration of only two months. The lesions presented as soft-tissue masses deep in the scalp with involvement of the underlying cranium in all eight of the cases in which roentgenograms or operative reports were available for review. Characteristically, there was erosion of only the outer table of the skull, although in three cases the lesion extended through the inner table to attach to the underlying dura mater. It was not possible to detect the exact site or origin, although origin from one of the deep fascial layers of the scalp or the underlying periosteum seems most likely. Microscopically, the lesion appeared to be a proliferation of loosely arranged fibroblasts which most closely resembled nodular fasciitis. Mitotic figures as well as foci of osseous metaplasia were present. Treatment consisted of excision of the mass with local resection or curettage of the affected underlying bone in some cases. Followup revealed a benign clinical course with no recurrent or aggressive behavior.

A staging system, based upon the experience of 1215 patients, was published by the American Joint Committee Task Force on Soft Tissue Sarcoma in 1977. A subset of these patients, 594, was selected to study recurrence-free survival time. The authors found 331 patients with a recurrence within 5 years (100 local only, 123 metastatic only, and 108 local + metastatic); median months to recurrence was 9.7. Within 5 years, recurrence was clearly associated with mortality: among the 331 patients who experienced a recurrence, 245 died, whereas only 31 died among the 263 who had no recurrence. To further evaluate the utility of the published staging system, a multivariate analysis of five factors was carried out for 297 of the 594 patients (patients with unknown information for any one of these factors were excluded). Factors in addition to grade that exerted a significant influence on recurrence were: direct extension, symptoms, and location of tumor when survival was measured to the first of any recurrence, and tumor size, measuring survival to the first metastatic recurrence. It is therefore recommended that these factors be taken into account in staging this disease. Estimates of probable recurrence-free survival time based upon the multivariate model (Weibull) are also presented.