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The distribution of the beta-subunit of platelet-derived growth factor receptor (PDGFR-beta) was assessed by a sensitive immunoalkaline phosphatase technique using the monoclonal antibody PR7212. Frozen tissue sections of several nonneoplastic human tissues were stained along with 42 soft tissue sarcomas, 16 benign soft tissue proliferations, and 7 epithelial tumors. In all nonneoplastic tissue, there was intense labeling of cell processes of perivascular fibroblasts or pericytes in and about the walls of muscular blood vessels and of fibroblast cell processes around some glandular and ductal epithelia. No PDGFR-beta was found in the endothelial cells of muscular arteries and veins, but cells of uncertain identity within some capillaries were immunoreactive and the possibility that endothelial cells of some small capillaries express PDGFR-beta could not be excluded. In kidney there was strong labeling of glomerular mesangial cells and interstitial fibroblasts. Some histological types of soft tissue sarcomas were uniformly and strongly labeled with anti-PDGFR-beta, but other types were infrequently labeled or unreactive. The order of decreasing frequency and strength of labeling of the various types of benign and malignant soft tissue proliferations was as follows: benign fibromatosis and neurofibroma greater than malignant fibrous histiocytoma greater than liposarcoma greater than leiomyosarcoma greater than rhabdomyosarcoma. No tumor cell labeling was detected in epithelioid, synovial or clear cell sarcomas, leiomyomas, or carcinomas, but there was usually strong labeling of fibroblast and/or pericyte cell processes within tumor, especially around blood vessels. We conclude that PDGFR-beta is strongly expressed by vascular and stromal tissues of most tumors and normal organs and by tumor cells of several types of soft tissue tumors and proliferations, most notably those of fibroblastic origin.

Increased expression of P-glycoprotein is associated with multidrug resistance (MDR) in many cell lines. Significant levels of P-glycoprotein have been detected in a number of human tumors. The purpose of this study was to determine whether P-glycoprotein expression correlates with both response to chemotherapy and prognosis in soft tissue sarcoma of childhood. In a retrospective study, biopsy samples from 30 cases of rhabdomyosarcoma (RMS) and undifferentiated sarcoma (US) treated at The Hospital for Sick Children in Toronto were analyzed using a semiquantitative immunohistochemical procedure. P-glycoprotein was detected in nine patients, four at diagnosis, and five at subsequent biopsy. All nine patients relapsed after a clinical response (complete [CR] 55%, partial [PR] 45%) to chemotherapy. Twenty of 21 patients with consistently P-glycoprotein-negative tumors received chemotherapy and they all responded clinically (CR 80%, PR 20%). Only one of these 20 patients has relapsed. The probability of relapse-free survival was significantly different (P less than .000000012) in chemotherapy-treated patients whose tumors contained detectable levels of P-glycoprotein (n = 9), compared with those whose tumors contained no detectable P-glycoprotein (n = 20). The overall probability of survival was also significantly different in these two groups (P less than .0000267). Both relapse-free and overall survivals remained statistically different in the two groups of patients when analyzed by the log-rank method, after adjustment for differences in stages and sites. The incidence of other adverse prognostic factors in the two groups, for example, younger and older ages, low pretreatment lymphocyte counts, large tumors, and unfavorable histology were not significantly different. Thus, detectable P-glycoprotein appears to be an important adverse prognostic factor in children with soft tissue sarcoma, and consistent absence of the protein is associated with a favorable prognosis.

The nuclear DNA content of 148 high-grade soft tissue sarcomas of the extremities and trunk was determined by flow cytometry, using tumor material from paraffin-embedded tissue. The patients were part of a prospective randomized clinical trial on the efficacy of adjuvant single-agent chemotherapy with doxorubicin. Chemotherapy did not improve the metastasis-free survival (MFS). After a median follow-up time of 48 months (range, 2 to 97), a multivariate analysis of prognostic factors for developing metastatic disease was performed. DNA aneuploidy was found to be an independent prognostic risk factor in addition to histologic malignancy grade IV, intratumoral vascular invasion, tumor size over 10 cm, and male sex. Patients with none or one risk factor had a 5-year MFS of 79%, with two risk factors 65%, with three risk factors 43%, and with four and five risk factors 0%. About one half (78 of 148) of the patients with three factors or less belonged to a group with a MFS over 60%. The combination of different risk factors, including DNA aneuploidy, seems to be a useful prognostic model for soft tissue sarcomas, which could be of value to select high-risk patients for further trials with adjunctive therapy.

Masson's vegetant hemangioendothelioma is a benign intravascular tumor, sometimes confused with such malignant vascular tumors as angiosarcoma, whose clinical appearance is nonspecific and whose diagnosis can only be established through microscopic examination. The fine needle aspiration (FNA) cytologic findings together with the histologic and immunohistochemical findings of such a tumor in a 22-year-old man are presented. Cytologically, the material obtained by FNA consisted of two distinct populations of cells. One type of cell had large nuclei (sometimes displaced towards the periphery), finely granular chromatin, prominent nucleoli and abundant globular cytoplasm. The second type of cell had spindle-shaped or oval nuclei, granular chromatin and scanty eosinophilic cytoplasm. Although these findings may permit the cytologic recognition of this entity, the aspirate in this case was interpreted as showing a vascular mesenchymal tumor of probable malignancy. Histologic examination of the excised tumor, aided by immunoperoxidase studies for factor VIII antigen that revealed the endothelial nature of the proliferating cells, established the correct diagnosis.

Twelve cases of alveolar soft part sarcoma (ASPS) were reviewed. Seven of them arose primarily in the lower extremities, three in the head and neck region, and two in other parts. ASPSs in the head and neck region occurred in children before 10 years of age, whereas ASPSs in the other regions occurred in rather older patients. Moreover, ASPSs of the head and neck were relatively small in size, and were diagnosed earlier than those in other regions. Histologically, six cases (including all the head and neck cases) contained considerable area of small and indistinct alveolar structures. Four cases showed remarkable cellular pleomorphism. Immunohistochemical demonstration of vimentin, desmin, the beta-subunit of enolase and the MM isozyme of creatine kinase, together with the absence of immunoreactive cytokeratin, supported the myogenic nature of this rare tumor. A small number of S-100 protein-positive tumor cells were also observed. Follow-up data for these cases disclosed that the tumors containing considerable area of small alveoli and uniform small tumor cells formed distant metastases at an early stage.

The immunohistochemical expression of cytoskeletal proteins in alveolar soft part sarcoma (ASPS) was studied by light and electron microscopy. Of the five cases examined by the avidinbiotin-peroxidase complex method, variable numbers of immunoreactive cells for desmin were found in three, for vimentin in two, for muscle-specific actins in three, and for alpha-smooth muscle actin in four. Immunoelectron microscopic study demonstrated that desmin and vimentin were localized on whorled bundles of intermediate filaments in the perinuclear cytoplasm. In addition, a few dispersed intermediate filaments became evident in specimens treated with saponin and fixed with tannic acid. These immunohistochemical results indicate that a few tumor cells of ASPS may express some properties of the cytoskeleton of smooth muscle cells in addition to those of skeletal muscle cells. Considering the discrepancies reported in the actin isoforms demonstrated in myogenic tumors, we conclude that ASPS is probably a peculiar, primitive myogenic tumor that does not show any distinctive features of rhabdomyogenic or leiomyogenic differentiation.

Malignant granular cell tumor is an exceedingly rare tumor and only a few cases are documented in the literature. We report a malignant granular cell tumor of the subcutaneous tissue of the thigh in a 59-year-old man, and discuss the ultrastructural and immunocytochemical findings and their diagnostic value.

To date, the histogenesis of alveolar soft part sarcoma has been considered to be of paraganglioma origin, striated muscle cell origin, or as a malignant granular cell myoblastoma, neural neoplasm, or renin-producing tumor. Further studies for these existing theories were performed based on various methods. The negative formaldehyde-induced fluorescence and the immunohistochemical absence of neuron-specific enolase were against the paraganglioma theory. The immunohistochemical absence of myelin proteins (P2 protein and PO protein) and S-100 protein were against the malignant granular cell myoblastoma and neural neoplasm theory. Furthermore, there was a totally negative immunohistochemical finding for renin in the tumor cells, and the biochemical relationship of the tumor and renin was completely negated. The contradiction in a well-known report that the components of crystals were considered to be Z-band materials such as tropomyosin was referred to based on recent myological data. Concurrently, the absence of tropomyosin was immunohistochemically demonstrated. Hence, the issues on the histogenesis of alveolar soft part sarcoma and the identity of the characteristic crystalloids remain open for discussion.

A clear cell sarcoma that developed on the left back of a 19-year-old Japanese female was studied ultrastructurally. The findings included basal laminae, desmosomelike junctions, cytoplasmic interdigitations, lamellar bodies, and immature melanosomes. These findings suggest schwannian differentiation of this tumor, since they are not usual features of malignant melanoma except for melanosomes. Therefore this tumor seems to be more akin to malignant schwannoma than to malignant melanoma.

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 evidence suggests that the steroid hormones may influence the biologic course of tumors of soft tissue. In an attempt to characterize the possible steroid hormone dependency of soft tissue, we studied the incidence and distribution of cytosolic receptors for the steroid hormones in benign and malignant tumors of adipose tissue origin. All specimens were assayed for the steroid hormone receptors by charcoal dextran technique and analyzed by the method of Scatchard. The results show a high incidence of cytosolic estrogen and glucocorticoid receptors in tumors of adipose tissue origin except in lipoma and well differentiated liposarcoma. The binding parameter of these receptors suggests that the receptors may be responsive to physiologic steroid hormonal milieu.

Outside the central nervous system S-100 is found only in Schwann cells and satellite cells of ganglia. It has also been demonstrated in Schwannomas and neurofibromas but is absent from soft tissue tumors of non-neural origin. S-100 protein was looked for in granular cell myoblastomas using an immunohistochemical technique in an attempt to further elucidate the histogenesis of these tumors. All tumor cells in the ten tumors studied were intensely stained with antiserum to S-100 including one with some malignant features. These results support the idea that granular cell myoblastomas arise from Schwann cells.

Nine cases of malignant "triton" tumors, based on the coexistence of rhabdomyoblasts and Schwann cell elements, were analyzed clinicopathologically and immunocytochemically. All tumors were stained for myoglobin and S-100 protein by the immunoperoxidase technique. Six of the nine patients were in the third or fourth decade of life. Six cases were associated with von Recklinghausen's disease, and the tumors in two cases grew along nerve trunks. The malignant tumors showed a predilection for the thigh and buttock. Six of the seven deaths occurred within two years of the initial treatments. Strongly positive staining for S-100 protein was observed in three tumors, with transitional zones between the sarcomas and peripheral neurofibroma-like areas, as well as in two tumors composed predominantly of rhabdomyoblastic elements. In four other cases the tumors were only weakly positive for protein S-100. Intracytoplasmic myoglobin was present in all cases. Tumors composed predominantly of rhabdomyosarcomatous elements occurred in four patients, including two children with von Recklinghausen's disease. These results, considered with other findings, suggest that malignant "triton" tumors may not be as rare as previously believed.

The type, differentiation and histogenesis of the tumor cells of alveolar soft part sarcoma (ASPS) have been analyzed in a series of ten cases by a light-microscopic, ultrastructural, immunohistochemical and cytologic investigation and quantitative DNA analysis. Four tumors deviated from ordinary ASPS: three were wholly or partly of the so-called pleomorphic variant of ASPS and a fourth tumor showed calcifications of the psammoma body type. The ultrastructural findings and immunohistochemical demonstration of desmin supported the hypothesis of a rhabdomyomatous differentiation and gave no support to epithelial (negative immunoreactions for cytokeratins, epithelial membrane antigen, HMFG-1 and -2, tissue polypeptide antigen (TPA] or neuroectodermal (negative for S-100 protein, glial fibrillary acidic protein, neurofilaments) differentiation. The negative immunoreactions for vimentin and myoglobin and the positive reaction for neuron specific enolase (NSE) do not exclude a rhabdomyomatous differentiation since in rhabdomyosarcomas the undifferentiated rhabdomyoblasts generally contain vimentin and the differentiated tumor cells contain myoglobin and rhabdomyosarcoma has previously been reported as being positive for NSE. The production of external lamina material peripherally in the tumor cell nests and around vessels in the vascular septa was demonstrated both ultrastructurally and by immunohistochemistry using antibodies against collagen IV and laminin. The cytologic appearance in smears obtained by fine-needle aspiration from a case of the pleomorphic variant showed some resemblance to that of a carcinoma. The seven tumors with an ordinary cell appearance were found to show a diploid DNA-distribution at a quantitative analysis performed on paraffin sections, while the three tumors wholly or partly of the pleomorphic type showed an additional tetraploid peak.

The intermediate filament cytoskeleton of various types of human soft tissue tumors was analyzed by immunofluorescence microscopy with the use of specific antibodies against cytokeratins, vimentin, and desmin, as well as by one- and two-dimensional gel electrophoresis of high-salt buffer- and detergent-resistant cytoskeletal preparations. All leiomyomas as well as a leiomyosarcoma contained desmin. Leiomyomas of both gastrointestinal and uterine derivation and the retroperitoneal leiomyosarcoma showed strong reaction for desmin in the smooth muscle cells, but the latter two exhibited also vimentin staining. In embryonal rhabdomyosarcomas, desmin prevailed in the large, apparently well-differentiated rhabdomyoblasts; whereas the smaller, less differentiated tumor cells preferentially contained vimentin. Cells of malignant fibrous histiocytomas were characterized by their content of vimentin as the only intermediate filament protein present. In alveolar soft part sarcoma, a rare tumor of hitherto unknown histogenesis, vimentin and desmin co-existed within the same tumor cells, indicating, together with chemical determinations, the myogenic derivation of this neoplasm. The results show that immunologic and biochemical analysis of proteins associated with the intermediate filament cytoskeleton is a useful adjunct in the diagnosis of diverse neoplasms, particularly those with equivocal histologic features, and thus aids in the histogenetic classification of soft tissue tumors.

The paper presents immunofluorescence findings on the distribution of medium-sized vimentinic and cytokeratinic filaments in the cells of epithelioid sarcoma. Two morphologically different types of tumor cells have been shown to be distinguished by the pattern of their filament expression: fusiform fibroblastoid cells contain vimentin (a mesenchymal type of differentiation), but there is a coexpression of cytokeratin and vimentin (an epithelial type) in the so-called epithelioid cells. Double mesenchymal-and-epithelial differentiation of the cells makes it possible to suppose that this tumor is of mesodermal rather than mesenchymal origin as is generally accepted. The features found in the distribution of medium-sized filaments in the epithelioid sarcoma may be useful in the practical differential diagnosis of this tumor as compared to numerous morphologically similar neoplasms.

The distributions of laminin, fibronectin, and interstitial collagen type III have been investigated in a series of 60 soft tissue tumours by immunochemistry. Positive laminin staining was seen in sites predicted by the distribution of ultrastructurally visible basal lamina. Pericellular laminin was present in all benign tumours of Schwann cell and smooth muscle origin examined, in the two malignant Schwannomas examined, and in six of 13 leiomyosarcomas. It was also evident around nests of cells in an alveolar soft part sarcoma and around malignant endothelial cells in an angiosarcoma. In fibroblastic and fibrohistiocytic tumours it was found only in blood vessel walls. The results of laminin staining led to revision of the original histopathological diagnosis in seven of the 60 cases studied. Fibronectin was abundant in the stroma of most neoplasms, both benign and malignant. It was also found in a distribution parallel to that of laminin. In some tumours this was clearly distinguishable from the distribution of interstitial collagen. Intracellular fibronectin was shown consistently only in mast cell granules. Its demonstration in synovial cells, fibroblasts, and histiocytes was more variable. Interstitial collagen type II had the most irregular distribution of the three proteins. It was as plentiful in tumours of smooth muscle origin as in tumours of fibroblastic origin, but was scanty in fibrous histiocytomas. Its distribution appeared similar to that of laminin and fibronectin in leiomyomas, but differed from these two proteins in Schwann cell tumours and other neoplasms. In one leiomyosarcoma fibronectin, laminin, and type III collagen appeared to be lost concomitantly from tumour cell peripheries.

The types of collagen present in a case of elastofibroma dorsi were determined using type specific, characterized collagen antibodies. The presence of type II collagen (normally present only in articular cartilage and in selected ocular structures) is discussed with regard to the pathogenesis of this lesion, and the use of collagen antibodies is discussed with regard to their potential value in better characterizing and classifying mesenchymal tumors.

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."

One hundred five patients undergoing therapeutic oophorectomy for metastatic breast cancer (n = 105) from 1975 to 1985 were reviewed. There were 54 responders (51%) to oophorectomy, with a median duration of response of 16 months (range, 3 to 129 months). Thirty of 42 (71%) estrogen receptor (ER)-positive patients responded to oophorectomy versus five of 24 (21%) ER-negative patients (P less than 0.001). Of the 39 patients with unknown ER status, 19 (49%) responded to oophorectomy. Osseous, soft tissue, and pulmonary metastases responded at similar rates. Of the 16 patients who had received adjuvant chemotherapy, there were five responders (31%) to oophorectomy. Second-line endocrine therapy was effective in 29 of 53 (55%) patients. Fifteen of 28 (54%) ER-positive patients responded to second-line endocrine therapy while two of six (33%) ER-negative patients responded. Twenty-three of 37 (62%) oophorectomy responders responded to second-line endocrine therapy versus six of 16 (38) nonresponders. Oophorectomy appears to be a valuable palliative treatment for metastatic breast cancer. ER-positive patients have the best chance of responding to this therapy. However, ER-negative patients have a reduced but definite chance of responding with a good duration of response. Response to further endocrine treatments is predicted by response to oophorectomy and to a lesser degree by ER status.

The staining pattern by Ricinus communis agglutinin (RCA), a lectin used as a good marker for histiocytes, in 24 cases with malignant fibrous histiocytoma (MFH) was studied and compared with that of 12 cases of fibrosarcoma (FS). In 20 (83%) of 24 cases of MFH, varying degrees of RCA binding were observed, whereas only four (33%) of 12 cases of FS were positive. RCA-positive FS included three cases with infantile FS and one adult case with post-radiation FS. Eight adult patients with FS were entirely negative. This positivity rate of RCA binding in MFH was much higher than those of antisera against lysozyme, alpha-1-antitrypsin, and alpha-1-antichymotrypsin previously reported. Seven MFH patients with focal aggregation of RCA-positive benign-appearing (reactive) histiocytes died earlier than the other patients with only scattered RCA-positive histiocytes; 5-year survival rates were 32% and 69%, respectively (p less than 0.05). These findings suggest that RCA reactivity can be used as a potential diagnostic and prognostic marker for MFH.

Sixty-six human soft-tissue sarcoma specimens were assayed for incidence and distribution of steroid hormone receptors. Liposarcomas (43%) and leiomyosarcomas (60%) had a high incidence of estrogen receptor. In contrast, sarcomas of fibrous and synovial tissue origin lacked any detectable receptor for estrogen. Malignant fibrous histiocytoma had the highest incidence of glucocorticoid (66%) and androgen (66%) receptors. The incidence of receptors for estrogen and glucocorticoid was higher in female than in male patients (62% and 38%, respectively). Sucrose density gradients demonstrated 8s-type receptors for both estrogen and glucocorticoid. Data from this study suggest that specific high-affinity cytosolic receptors for steroid hormones are present in human soft tissue sarcoma and that their distribution may depend on the histogenetic origin and the sex of patients.

Ten cases of fibroma of the tendon sheath were examined by means of histological, topochemical, and immunohistochemical methods. Investigations were aimed at re-evaluation of histological variability and definition of diagnostic criteria. Microscopic observations suggested the following features to be typical of fibroma of the tendon sheath: Primitive mesenchymal or fibroblastic cells without further differentiation, slit- and cleft-like spaces with lining cells decorated by endothelial markers, and collagenous, cartilaginous or myxoid basic substance at least in areas rich with sulphated glycosaminoglycans. Differential diagnostic distinction of tendon sheath fibroma from myxoid cartilage tumors, fasciitis nodularis, and myxoid fibromatosis as well as from fibrohistiocytic lesions and giant cell tumors of tendon sheath is discussed with reference to the above definition.

Myoglobin has been detected by the immunoperoxidase technique in the cytoplasm of nonmuscular cells present in malignant tumors infiltrating skeletal muscle. The positive cells were reactive histiocytes in one case, and malignant cells (breast carcinoma, malignant melanoma, and malignant lymphoma) in the others. These findings indicate the need to exercise caution in the interpretation of myoglobin stain for the diagnosis of rhabdomyosarcoma under these circumstances.

Histological localization of myosins of the smooth and skeletal muscles was investigated in comparison with that of myoglobin by immunoperoxidase technique using the antibody against each of them in surgical specimens from spindle cell tumors and tumor-like lesions of the soft tissue. Skeletal muscle myosin was demonstrated in all of the cases of rhabdomyosarcoma, whereas myoglobin was found in 75% of the examined cases. Smooth muscle myosin was widely distributed not only in the tumor cells of smooth muscle origin such as leiomyosarcoma and angioleiomyoma, but also in the tumor cells showing myofibroblastic differentiation such as malignant fibrous histiocytoma and in the epithelial components of synovial sarcoma. The results showed that skeletal muscle myosin can be regarded as an excellent marker in the diagnosis of rhabdomyosarcoma and that smooth muscle myosin is a useful marker of leiomyosarcoma and leiomyomas, and of tumors with myofibroblastic differentiation.

Proliferative activity of soft tissue sarcomas (STS) in 34 cases was estimated by immunohistochemical procedures (avidin-biotin complex [ABC] method) with monoclonal antibody Ki-67 which reacts with a nuclear antigen expressed in all phases of cell cycle except G0. In 20 of 34 cases (59%), varying numbers of Ki-67-positive tumor cells were detected with a range from 5 to 382 per 10 high power fields (HPF) (mean 57.2/10 HPF). Ki-67 index (the number of Ki-67-positive tumor cells/10 HPF) positively correlated with mitotic count (r = 0.428, P less than 0.02), cellularity (r = 0.447, P less than 0.01), and histologic grade (r = 0.473, P less than 0.01). The Ki-67 low index group (less than 50/10 HPF) showed more favorable prognosis than the high index group (more than 50/10 HPF) (P less than 0.005). Three cases with low mitotic count and unfavorable prognosis were proved to be the Ki-67 high index group (142-382/10 HPF). These results indicated that reactivity of tumor cells for Ki-67 is a useful prognostic marker in the patients with STS, and might be used as one of the histologic factors for the grading of STS.

Fibrous hamartoma of infancy is an uncommon lesion, the histogenesis and biological nature of which are uncertain. Ten cases have been studied by light microscopy, mucin histochemistry and immunohistochemistry. The typical histological features are presented. The presence of hyaluronic acid and of chondroitin-4- and -6-sulphate and keratan sulphate has been demonstrated in different components of the tumour. Vimentin positivity was noted in the undifferentiated and fibroblastic components. The implications of these findings are discussed. Whether the lesion merits the designation of hamartoma or is, in fact, a benign neoplasm remains obscure.

Clear cell sarcoma (CCS) is an uncommon, clinicopathologically distinct neoplasm that typically arises in association with tendons and aponeuroses. It shares several histologic and ultrastructural features with malignant melanoma. Clear cell sarcoma occasionally may be confused with other tumors of soft tissue that have a predominantly epithelioid appearance, including epithelioid leiomyosarcoma, epithelioid neurofibrosarcoma, synovial sarcoma, and epithelioid sarcoma. To assess the potential contribution of immunohistochemistry to this differential diagnosis, a panel of immunostains was applied to examples of each of these neoplasms. All six CCSs contained vimentin, and five were reactive with the melanoma-specific monoclonal antibody HMB-45. In addition, five CCSs expressed neuron-specific enolase, four cases displayed S100 protein, and four examples contained LN3 antigen. Synaptophysin and Leu-7 antigen were present in one case each. Cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, desmin, muscle-specific actin, and leukocyte common antigen were invariably absent. No other primary epithelioid neoplasm of soft tissue reacted with HMB-45. Clear cell sarcoma could be separated from epithelioid leiomyosarcoma by the presence of desmin and muscle-specific actin in the latter neoplasm. Similarly, both synovial sarcoma and epithelioid sarcoma differed from CCS by their expression of cytokeratin and epithelial membrane antigen. Clear cell sarcoma and malignant melanoma were immunohistochemically indistinguishable, supporting the concept that they share a common pattern of differentiation.

This combined ultrastructural and immunohistochemical study of four alveolar soft-part sarcomas analyzes the characteristic granules in order to elucidate the histogenesis of this unusual neoplasm. The granules have the ultrastructural features and staining characteristics of renin, react with antiserum to renin, and like renin, incorporate zinc into the crystalline storage granules. The cell appears to be a modified smooth muscle cell analogous to renal juxtaglomerular cells and the cells of juxtaglomerular cell tumors. As there is no association with hypertension, it would appear that alveolar soft-part sarcomas either do not secrete or the product is a form of renin that does not act upon the angiotensin system.

Anti-rat myoglobin (Mb) was prepared and used in the avidin-biotin-peroxidase complex (ABC) method on paraffin-embedded sections of nine soft tissue tumors (including two rhabdomyosarcomas) of rats. Distribution and nature of the reactive substance to Mb antiserum were compared to those of desmin antiserum. Rat Mb was isolated from the skeletal muscle; monospecificity of the rat antiserum was confirmed by the immunoblotting procedures. The Mb antiserum reacted specifically to normal and neoplastic striated muscle cells. Mb-staining reactions were present diffusely in the cytoplasm, while desmin-staining substances were localized at Z-bands or were diffuse in the cytoplasm as separated aggregates. Reaction to the Mb serum was also detected in cells of thick portions of Henle's loop and distal convoluted tubules.

According to the autocrine hypothesis of cell growth, tumors, in contrast to normal tissue, might simultaneously express both a growth factor and its receptor, resulting in autoregulation and autostimulation of growth. In a related hypothesis, expression of either a growth factor or receptor might allow a tumor to escape exogenous controls on growth, and thereby correlate with malignant potential. Using immunohistochemistry, we investigated these hypotheses in 69 human soft tissue tumors (STT) by assaying for the expression of nerve growth factor and receptor, epidermal growth factor and receptor and platelet-derived growth factor. Both benign (B) and malignant (M) STT expressed a variety of factors and receptors. However, the frequency of any growth factor expression (90% M versus 55% B, p = 0.002) and of multiple factors (59% M versus 24% B, p = 0.006) was significantly greater in malignant tumors. Similarly, expression of any growth factor receptor (73% M versus 31% B, p = 0.001) and of multiple receptors (35% M versus 3% B, p = 0.002) was significantly more frequent in malignant STT. In terms of the autocrine hypothesis, growth factor/receptor co-expression was significantly more common in malignant STT (63% M versus 17% B, p = 0.0002). We conclude that (a) expression of both single and multiple growth factors and receptors was significantly more frequent in malignant STT; (b) support for an autocrine growth mechanism through simultaneous factor/receptor co-expression can be found in both benign and malignant STT; (c) co-expression, however, was more frequent in the malignant tumors; and (d) overall, growth factor and receptor expression, as well as co-expression, was related to biologic potential among human soft tissue tumors.

Clinical observations showed that the natural history of sarcomatous lesions may be different among males and females, and it may be influenced by hormonal factors. Estrogen receptors (ER) were measured on biopsy specimens of melanoma (two patients), soft-tissue sarcoma (four patients), cystosarcoma phylloides (five patients), benign breast tissues (27 patients), and breast carcinoma (109 patients). Thirty-four specimens also had progesterone receptors (PR) analyzed. One of the five cystosarcoma phylloides and five of the six nonmammary sarcoma tissues contained ER (mainly of the 4 Svedburg (S) variety) of more than 7 femtomoles (fmoles)/mg cytosol proteins (6/11 = 54%). For comparison three of the 14 fibroadenoma specimens and two of the 13 patients with other benign lesions had positive ERs (5/27 = 19%), whereas 56% of the breast carcinomas were ER positive. Since the amount of 8S ER found in sarcomatous tissues is relatively low, hormonal treatment would not be effective.

A man with malignant fibrous histiocytoma of the thigh had avid uptake of Tc-99m MDP in the lesion. Review of tissue sections showed considerable accumulation of iron in the tumor. Iron is known to be a potential nidus for deposition of the Tc-99m diphosphonates. A review was made of tissue sections from two other reported cases of malignant fibrous histiocytoma which also had significant accumulation of Tc-99m diphosphonates. Both revealed iron within the tumor. The origin of the iron is unknown (perhaps from necrosis and hemorrhage, from trauma, or from innate phagocytic activity of the histiocytes). However, this observation may serve as a stimulus to studies attempting to discern the underlying mechanisms of extraosseous deposition of the Tc-99m diphosphonates.

Formalin-fixed histologic and acetone-fixed cytologic preparations from 87 surgically removed subcutaneous and soft tissue canine tumors were examined for immunoreactivity to cytokeratin, desmin, and vimentin. The avidin-biotin complex (ABC) technique demonstrated immunoreactivity in both preparations, but the intensity and specificity of the reactions were dependent on the primary antibody. Polyclonal antibodies to cytokeratin were more consistent in immunoreactivity than were polyclonal desmin or vimentin antibodies. The monoclonal antibody proved more satisfactory for demonstrating vimentin than the polyclonal antibody. Greater dilutions of primary antibodies may be used on cytologic preparations than on histologic sections. Evaluation of cytologic preparations may be inconclusive due to background staining, scant cellularity, or poor cytoplasmic preservation.

We carried out DNA cytofluorometry with propidium iodide stain on the 17 cases of soft tissue tumors including giant cell tumor of the tendon sheath, pigmented villonodular synovitis, 2 hemangiomas, 3 lipomas, 5 schwannomas, 3 neurofibromas, liposarcoma and synovial sarcoma. The benign tumors were characterized by regular polyploidization with very few S-phase cells, indicating slow tumor growth. Most of the malignant soft tissue tumors were associated with remarkable polyploidization with an increase in S-phase cells. However, some malignant tumors did not show polyploidization. We concluded, therefore, that an increase in S-phase cells is an important, cytofluorometric criterion for malignancy of soft tissue tumors.

An immunohistochemical investigation of chorionic gonadotropin (CGT) in normal placental, hydatidiform mole and choriocarcinoma tissues was undertaken. Cyto- and syncytiotrophoblast both were shown to produce the hormone in normal and tumor trophoblast; the rate of synthesis increased in proportion to the degree of cell elements differentiation, except for very large elements of syncytiotrophoblast with numerous pycnotic nuclei which were found to contain either only traces of response to CGT or none at all. The percentage of syncytiotrophoblast--produced hormone progressively increased in the succession of the placenta--hydatidiform mole--choriocarcinoma. No significant difference in the levels of immunohistochemically--identified hormone was found in the hydatidiform mole and choriocarcinoma.

The clinicopathologic, ultrastructural and immunohistochemical features of eleven cases of clear cell sarcoma are described. There were 6 males and 5 females with an average age of thirty-six (10-59 years). Tumors were found arising from the tendons, aponeuroses and fascial structures with a predilection for the lower and upper extremities. Follow-up data was available in 8 patients. Five of them are alive. Nevertheless, 3 of the five showed evidence of recurrence or metastasis. The other 3 patients died of tumor with metastasis. Microscopically, the tumors were composed of short fascicles of fusiform cells with a clear to eosinophilic cytoplasm and vesicular nuclei with prominent nucleoli. Melanin was demonstrated in 5 cases and S-100 was known present focally in all cases, but no positive keratin staining was obtained. Electron microscopic studies revealed cell attachments and mature melanosomes. The exact histogenesis remains obscure, but our ultrastructural and immunohistochemical findings support the idea of neural crest origin of this tumor.

Immunohistochemical analysis of 40 formalin-fixed, paraffin-embedded malignant melanomas (12 primary mucosal, 16 primary cutaneous, and 12 metastatic cutaneous) was performed to study the possible differences in immunostaining profiles according to location. The majority of melanomas were reactive with a polyclonal antibody to S100 protein (P-S100; 85%), a monoclonal melanoma-specific antibody (HMB-45; 88%), and a monoclonal antibody to vimentin (90%), and there were no differences in staining profiles for these antibodies by anatomic location. In contrast, while 13 of 16 cutaneous melanomas (81%) and ten of 12 metastatic melanomas (83%) were reactive with a monoclonal antibody to S100 protein (MoAb-079), only five of 12 mucosal tumors (42%) showed positive staining for MoAb-079. Similarly, 14 cutaneous melanomas (88%) and 11 metastatic melanomas (92%) showed positive staining for neuron specific enolase (NSE), while only four mucosal melanomas (33%) were NSE-positive. Of the 40 melanomas, all but two were reactive with either P-S100, MoAb-079, or HMB-45. These findings suggest that MoAb-079 and NSE may be less sensitive markers than P-S100 and HMB-45 for routinely processed mucosal melanomas as compared with cutaneous and metastatic tumors.

16 spontaneous tumors of the peripheral nerves and 18 spontaneous tumors of mesenchymal origin in BDVI rats were studied by peroxidase-antiperoxidase method using anti-serum (DAKOPATT) against protein S-100. The majority of spontaneous peripheral nerve tumors were of cystic histological structure identical to that of cystic neurinomas induced in rats by ethylnitrosourea and almost all of these tumors were S-100 protein positive. The incidence of spontaneous neurinomas in BDVI rats was in some experiments as high as 5%. All tumors of mesenchymal origin (except one lipoma) were S-100 protein negative: 2 fibromas, 6 fibrosarcomas, 3 malignant fibrous histiocytomas, one rhabdomyosarcoma and one hemangioendothelioma. S-100 protein is found, as in human pathology, useful for distinguishing tumors of schwann cell and mesenchymal origin in rats.

The histogenesis of Ewing's sarcoma (EW) and extraskeletal Ewing's sarcoma (EEW) is still disputable. Their relationship to the so-called Askin's tumor, neuroectodermal tumor of bone, and peripheral neuroblastoma remains to be established. In an attempt to clarify these points, immunocytochemical and ultrastructural studies were done on tissues from 14 cases of EW, 4 cases of EEW, and 9 cases of primitive neuroectodermal tumor (PNET) and compared with neuroblastoma and olfactory neuroblastoma. Six tumors categorized initially as EW and EEW on biopsy, turned out to be PNET by extensive histologic and/or ultrastructural observations. Abundant glycogen was recognized not only in 16 of 18 cases of EW and EEW, but also in seven of nine cases of PNET. Fine fibrillar cell processes were seen between tumor cells, at least in limited areas even in cases of EW and EEW. Immunocytochemically, neuron-specific enolase (NSE), neuroblastoma cell surface antigen (NBCA), neuron cell surface antigen (NCSA), and neurofilament (NF) were demonstrated not only in neuroblastoma, but also frequently in cases of EW, EEW, and PNET. The results seem to suggest that EW and EEW represent the most immature forms of neuroectodermal tumor. Electron microscopic study showed predominantly primitive cells with occasional areas of cell processes, neurosecretory granules, and microtubules, suggesting a neuroectodermal origin.

Eighteen cases of cellular schwannoma, a recently delineated benign entity, are described. These tumours present most often in middle-aged adults of either sex and show a predilection for the paravertebral region of the mediastinum and retroperitoneum. More than half the tumours macroscopically arose from a nerve but none was associated with von Recklinghausen's disease. The light microscopic features are remarkably consistent but are not immediately recognizable as neural in type. Means of distinction from a malignant nerve sheath tumour and from a variety of other soft tissue tumours are discussed. Immunohistochemical positivity for S-100 protein has been demonstrated in 17 of the 18 cases. Prolonged follow-up has revealed local recurrence in only one case; none has metastasized.

Seven cases of synovial sarcoma (SS), two with biphasic and five with monophasic histology, were studied immunohistochemically using monoclonal antibodies to intermediate filaments, keratin, and vimentin. Slender spindle cells and plump cells were constant components of all the tumors. Epithelioid cells were present only in biphasic SS. Epithelioid cells and plump cells were positively stained by both keratin and vimentin. Slender spindle cells were stained positive for vimentin and negative for keratin. Staining manner of each cell type was similar irrespective of monophasic or biphasic pattern. Present immunohistochemical studies suggested that monophasic or biphasic patterns in SS should be regarded as a different expression of the same disease. In addition, immunohistochemistry proved to be a useful tool to detect plump cells which were difficult to find on routine staining.

Intracellular myoglobin represents an excellent marker for specific characterization of normal (adult and fetal) and malignant skeletal muscle cells in paraffin sections. With an immunoperoxidase indirect sandwich technique for detection of intracellular myoglobin, positive staining was observed in 13 of 17 rhabdomyosarcoma specimens including 5 of 7 of the alveolar type, 5 of 5 of the embryonal type, and 3 of 5 of the pleomorphic type. Initial fixation in Zenker's-acetic acid solution gave optimal staining, but satisfactory results were obtained with fixation in formalin, Bouin's, and B5 solutions. Other types of sarcomas (13 cases) and other types of tumors (24 cases) that sometimes mimic rhabdomyosarcoma on histologic examination gave negative results. The immunoperoxidase method affords a sensitive and specific method for identifying rhabdomyoblasts in tissue on the basis of intracellular myoglobin and is of use in distinguishing rhabdomyosarcomas from other sarcomas and from malignant tumors of other types.

Described in this paper is a case of epithelioid haemangioendothelioma of soft tissue localised in the subcutis of the upper arm of a 47-year old man. The tumour was histologically characterized by cords and nests of plump epithelioid cells separated from each other by typical myxohyaline stroma. Light microscopy revealed also definite vasoformative areas and solid regions with vacuolization which were indicative of so-called intracytoplasmic vacuoles. Atypical nuclei were conspicuous findings. Ultrastructural and immunohistochemical investigations demonstrated the endothelial origin of the lesion. Immunohistochemical investigations also revealed the presence of cellular areas which produced positive response to "factor-VIII-associated antigen". Ultrastructurally the tumour cells exhibited densely packed microfilaments, 8 nm to 10 nm in thickness, and intracytoplasmic vacuoles. The latter were lined and delimited by single membranes, and some of these exhibiting luminal microvilli. The tumour cells exhibited typical pinocytotic vacuoles, with the cords or nests being encircled by thin basal membranes. Typical Weibel-Palade bodies were detectable in some cells. Also recordable from certain cells were intracytoplasmic crystalloid inclusion bodies of a kind never described before in the context of tumour cells of epithelioid haemangioendothelioma. Those inclusions were composed of substructural units of parallel electrodense lines, 19nm to 21nm in periodicity. The nature of epithelioid haemangioendothelioma and its relations with intravascular bronchiolo-alveolar tumours (IVBAT) and myxoid angioblastomatosis of bone were discussed in some detail.