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Upper gastrointestinal endoscopy was performed in patients with rheumatoid arthritis (RA) during the period 1989–1991, and biopsy specimens were obtained from the stomach and from the duodenum for examining amyloid deposits. Among 407 patients, gastrointestinal amyloidosis was confirmed in 54 (13.3%). Twenty-two patients were regarded as having slight amyloid deposits, while 32 patients were categorized as having marked amyloid deposits. The incidence of clinical manifestations suggestive of systemic amyloidosis was more frequent in the marked deposits group than in the slight deposits group (47% vs 14%, P < 0.05). Among the patients who died of manifestations associated with amyloidosis, the survival period following endoscopy was shorter in the marked deposits group than in the slight deposits group. These findings suggest that gastroduodenal biopsies may be useful for diagnosing secondary amyloidosis and that the degree of amyloid deposits seems to be correlated with the clinical manifestations of RA. [ABSTRACT FROM PUBLISHER]

The presence and distribution of N-myc gene product were studied in 13 neuroblastomas and five ganglioneuroblastomas, using immunohistochemical techniques. Nine tumors (eight neuroblastomas and one ganglioneuroblastoma of composite type) contained neuroblastoma cells with positive nuclei for N-myc protein. Microscopic examination showed that most of the positive neuroblastoma cells seemed to be immature, with no apparent neuronal differentiation. Nine of 11 tumours with amplified N-myc gene copies exhibited tumour cells with positive immunostaining for the N-myc gene product, while none of the seven non-N-myc amplified cases contained immunoreactive tumour cells. The survival of the patients positive for N-myc protein was significantly low compared with that of the negative ones. It is concluded that immunohistochemical staining for the N-myc gene product will facilitate prediction of the prognosis of patients with neuroblastoma. [ABSTRACT FROM PUBLISHER]

Background: Sarcoidosis is a benign systemic granulomatous disorder of unknown etiology. Cell-mediated immunity disorder is often found in sarcoidosis patients, and an association between malignant tumors and sarcoidosis has been suggested. Sarcoidosis and malignant disease can occur simultaneously or sequentially, leading to misdiagnosis and mistreatment. Sarcoidosis is diagnosed clinically, radiologically, and histologically. We report herein a case of sarcoidosis diagnosed by endobronchial ultrasound-guided transbronchial needle aspiration from the mediastinal lymph nodes of a breast cancer patient., Case Presentation: The patient was a 70-year-old Asian woman who presented with right breast tumor. A 20-mm movable mass was identified in the inferolateral quadrant of the right breast, and mammography revealed a spiculated mass with calcification. Ultrasonography revealed a mass with internal hypoechogenicity, and biopsy revealed estrogen receptor-positive, human epidermal growth factor receptor 2-positive invasive ductal carcinoma. Positron emission tomography/computed tomography showed multiple lymphadenopathy including mediastinal lymph nodes, with fluorodeoxyglucose accumulation in those nodes suggesting breast cancer metastases. Endobronchial ultrasound-guided transbronchial needle aspiration of a mediastinal lymph node revealed noncaseous epithelioid granuloma. Due to a history of uveitis and elevated soluble interleukin 2 receptor, lymphadenopathy due to sarcoidosis and stage IIA breast cancer were diagnosed. Right partial mastectomy and axillary lymph node dissection were performed after preoperative chemotherapy. No exacerbation of sarcoidosis symptoms has been observed during treatment., Conclusion: We report a case of breast cancer in which sarcoidosis could be diagnosed based on endobronchial ultrasound-guided transbronchial needle aspiration, a history of uveitis, and elevated soluble interleukin 2 receptor despite fluorodeoxyglucose positron emission tomography/computed tomography suggesting multiple lymph node metastases. This report emphasizes the importance of differential diagnosis of lymph node involvements in cancer patients., (© 2022. The Author(s).)

Background: Spontaneous regression (SR) is a rare phenomenon in which a cancer disappears or remits without treatment. We report a case of breast cancer that showed spontaneous tumor regression in the surgical specimen after core needle biopsy., Case Presentation: A 59-year-old woman came to our hospital complaining of a painful lump in the right breast. In the upper-outer quadrant of the right breast, a tumor with an unclear boundary, 30 mm in diameter, was palpable. In pathological findings from needle biopsy, the tumor was diagnosed as solid-type invasive ductal breast carcinoma. Partial coagulation necrosis was generated in estrogen receptor-negative, HER2-negative, and AE1/AE3-positive ductal carcinoma without infiltration of lymphocytes. Surgery for right breast cancer was then performed. Histological examination of the surgical specimen revealed the tumor was invasive ductal carcinoma with lymphocyte infiltration, coagulation necrosis, and fibrous tissue with hemosiderin. The tumor formed a solid nest, 3 mm in diameter, suggesting the possibility of SR., Conclusions: Immune responses, infection, hormones, surgical stress, and ischemia have been reported as mechanisms of SR. The findings in this case strongly suggest that SR of breast cancer is associated with anti-tumor immune responses.

Distant metastases from breast cancer are frequently found in bones, lungs and the liver. Metastasis to the stomach is rare, and its clinical presentation remains unclear. The present report describes a case of isolated gastric metastasis from breast cancer identified by contrast-enhanced computed tomography (CT). A 45-year-old female patient underwent right mastectomy and axillary lymph node dissection after preoperative chemotherapy for right invasive lobular breast carcinoma T4bN2M0, stage IIIB. Postoperative radiotherapy and endocrine therapy with tamoxifen for 5 years were performed. CT for postoperative follow-up at 52 years old revealed thickening of the stomach wall. Although the patient was asymptomatic, erosive mucosa was observed on the gastric body during gastroscopy. The gastric lesion was immunohistochemically diagnosed as metastatic luminal disease from the breast cancer. Positron emission tomography/CT revealed no abnormal accumulation suggesting metastasis to other organs. Palbociclib and fulvestrant treatment were initiated for gastric metastasis. Invasive lobular breast carcinoma results in gastrointestinal metastasis, including the stomach, more frequently than invasive ductal breast carcinoma. However, most gastric metastases occur simultaneously with systemic metastases. Solitary metastasis to the stomach without symptoms as in this case has rarely been reported. The possibility of gastric metastasis should be considered among the differential diagnoses, even in the absence of symptoms, when gastrointestinal abnormalities are seen on CT in patients with a history of breast cancer., (Copyright: © Kaneko et al.)

Primary duodenal adenocarcinoma is a rare disease, and cases with nodal metastases have a poor prognosis. A 46-year-old man complaining of bloody stool visited our hospital. Endoscopy, CT, and PET-CT showed adenocarcinoma in the 2nd portion of the duodenum. We performed radical resection (PpPD) and pathological findings showed T3N1M0 (Stage III). Chemotherapy consisting of FOLFOX6 was administered for 6 months after surgery. The patient was alive without recurrence 5 years later. This case suggests that adjuvant chemotherapy (FOLFOX regimen) following curative resection including lymph node removal is an effective treatment for cases with tumor involvement of the lymph nodes.

We report on a case of an infected urachal remnant successfully treated via a single-incisional laparoscopic technique. An 18-year-old woman was diagnosed with an infected urachal remnant. The center of the umbilicus was pulled and inverted from the skin, and the cephalic side of the urachus was dissected from the umbilicus. A single-incision laparoscopic technique employing ultrasonic coagulating shears was used to dissect the urachal remnant from the stump of the umbilicus to the caudal end. Single-incision laparoscopic excision of the urachal remnant can be used successfully as a minimally invasive technique with optimal cosmetic outcomes., (© 2016 Japan Society for Endoscopic Surgery, Asia Endosurgery Task Force and John Wiley & Sons Australia, Ltd.)

Background: Although cavernous hemangioma is one of the most frequently encountered benign hepatic neoplasms, hepatic sclerosed hemangioma is very rare. We report a case of hepatic sclerosed hemangioma that was difficult to distinguish from an intrahepatic cholangiocarcinoma by imaging studies., Case Presentation: A 76-year-old male patient with right hypochondralgia was referred to our hospital. Abdominal ultrasonography revealed a heterogeneously hyperechoic tumor that was 59 mm in diameter in segment 7 of the liver. Dynamic computed tomography showed a low-density tumor with delayed ring enhancement. Gadolinium-ethoxybenzyl-diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI) demonstrated a low-signal intensity mass with ring enhancement on T1-weighted images. The mass had several high-signal intensity lesions on T2-weighted images. EOB-MRI revealed a hypointense nodule on the hepatobiliary phase. From these imaging studies, the tumor was diagnosed as intrahepatic cholangiocarcinoma, and we performed laparoscopy-assisted posterior sectionectomy of the liver with lymph node dissection in the hepatoduodenal ligament. Histopathological examination revealed a hepatic sclerosed hemangioma with hyalinized tissue and collagen fibers., Conclusion: Hepatic sclerosed hemangioma is difficult to diagnose preoperatively because of its various imaging findings. We report a case of hepatic sclerosed hemangioma and review the literatures, especially those concerning imaging findings.

A 72-year-old woman with a sigmoid colon cancer and a synchronous colorectal liver metastasis (CRLM), which involved the right hepatic vein (RHV) and the inferior vena cava (IVC), was referred to our hospital. The metastatic lesion was diagnosed as initially unresectable because of its invasion into the confluence of the RHV and IVC. After she had undergone laparoscopic sigmoidectomy for the original tumor, she consequently had 3 courses of modified 5-fluorouracil, leucovorin, and oxaliplatin (mFOLFOX6) plus cetuximab. Computed tomography revealed a partial response, and the confluence of the RHV and IVC got free from cancer invasion. After 3 additional courses of mFOLFOX6 plus cetuximab, preoperative percutaneous transhepatic portal vein embolization (PTPE) was performed to secure the future remnant liver volume. Finally, a right hemihepatectomy was performed. The postoperative course was uneventful. The patient was discharged from the hospital on postoperative day 13. She had neither local recurrence nor distant metastasis 18 mo after the last surgical intervention. This multidisciplinary strategy, consisting of conversion chemotherapy using FOLFOX plus cetuximab and PTPE, could contribute in facilitating curative hepatic resection for initially unresectable CRLM.

Benign papillary mesothelioma of the peritoneum is an uncommon lesion that is usually discovered by chance during a surgical procedure. This lesion resembles metastatic carcinoma in gross appearance; therefore, intraoperative diagnosis can be difficult. This report presents a case of benign papillary mesothelioma concurrent with gastric cancer. The tumor was located on the hepatogastric ligament and resembled a metastatic peritoneal implant. A pathological review confirmed the diagnosis to be benign papillary mesothelioma.

A 73-year-old man was referred to our hospital with sigmoid colon cancer in July 2009. CT and MRI showed synchronous multiple liver metastasis. After a sigmoid colon resection in August, he received convergent chemotherapy in combination with 5-fluorouracil(5-FU)/Leucovorin(LV)(RPMI regimen)and bevacizumab for liver metastasis. After two courses without any major adverse effects, liver metastasis remarkably reduced on CT and MRI examination. We thus performed a liver resection, and pathological examination revealed a complete response in liver. Combination chemotherapy of 5-FU/LV and bevacizumab can be expected to provide safe and effective treatment for liver metastasis of colon cancer.

We treated two patients (each aged over 90 years) with Helicobacter pylori-negative nonsteroidal anti-inflammatory drug (NSAID)-caused duodenal ulcers, and had the opportunity to determine gastric acidity by means of 24-h pH monitoring. Endoscopic and histological examination showed no remarkable atrophic change in the gastric mucosa. The gastric pH was low throughout the day and night, and the gastric pH > or = 3 holding time ratio during 24 h was 17.1% and 25.8%, respectively in the two patients, so it was considered that they had gastric acid secretion of the same level as that in normal subjects of the same age or that in the young without H. pylori infection. Because of the complication of reflux esophagitis with a hiatal hernia, rabeprazole sodium, one of the proton pump inhibitors (PPIs), was administered and both patients made excellent progress. In conclusion, gastric acid secretion in patients with H. pylori-negative NSAID-caused duodenal ulcers is fully maintained even in the elderly, so PPIs may be the first choice of treatment.

Histologic observation of ovarian mucinous tumors suggests that there is a multistep transition through the accumulation of genetic alterations. We analyzed loss of heterozygosity (LOH) and replication error (RER) on TP53 and D17S855 as well as K-ras point mutations of the heterogeneous histologic areas of the same tumor in 26 cases of ovarian mucinous tumor. The laser capture microdissection (LCM) technique has been applied to the study of K-ras point mutation in 10 cases. As for genetic alterations for LOH or RER on TP53 and D17S855, 2 (1 borderline tumor and 1 carcinoma) of 14 cases and 4 (1 borderline tumor and 3 carcinomas) of 12 cases, respectively, showed genetic heterogeneities in different histologic areas. Six (2 borderline tumors and 4 carcinomas) of 18 cases showed heterogeneity of K-ras point mutation in the different histologic areas of the same tumor, and 5 (1 cystadenoma with Brenner tumor component, 2 borderline tumors, and 2 carcinomas) of 10 cases showed heterogeneous K-ras mutation pattern in the same tumor when the LCM technique was used. Atypical areas tended to show K-ras point mutations frequently. Out of 3 cases of mixed mucinous cystadenoma and Brenner tumor, 1 case showed K-ras point mutation in the Brenner tumor area but not in the area of mucinous cystadenoma. These preliminary results suggest that a subset of ovarian mucinous tumors occur through multistep carcinogenesis and show that LCM is useful for molecular pathologic studies., (Copyright 2001 by W.B. Saunders Company)

The authors report two cases with renal cell carcinoma (RCC) metastatic to the brain more than 10 years after nephrectomy. Case 1: An eighty-six-year-old female, on whom nephrectomy had been performed 12 years before, complained of alexia. Computed tomography (CT) revealed ring enhancement in the left temporoparietal region. Total removal of the brain tumor and irradiation of 18 Gy during surgery was performed. Histological examination showed metastatic brain tumor from RCC. The postoperative course was excellent. In the postoperative examination lung metastasis was found. Case 2: A sixty-seven-year-old male, on whom nephrectomy had been performed 15 years before, presented with right hemiparesis, aphasia and convulsion. CT showed two enhanced lesions, one of which accompanied with a hematoma in the left frontal lobe. Chest X-ray showed a coin lesion in the right lower lobe. Total removal of brain tumors was performed and 18 Gy irradiation was administered during surgery. Histological study revealed RCC. However, 3 months after surgery, a new lesion was recognized in the opposite hemisphere. The long interval of latency may be attributed to the slow-growing characteristic of renal cell carcinoma and the fact that renal cell carcinoma is under the influence of host immunity. Surgical treatment is recommended for patients who develop a solitary metastatic lesion or in whom other lesions are controlled and remain in a stable condition.

Two cases of intranodal myofibroblastoma, a rare primary spindle cell tumor of the lymph node, are described. The tumors arose in the inguinal or proximal region of the thigh of one middle-aged and one elderly Japanese male. The tumors were well-demarcated and composed of a fascicular proliferation of spindle cells with focal nuclear palisading and acellular stellate-shaped collagen-rich areas (so-called amianthoid fibers), and were associated with hemorrhagic areas. Immunohistochemically, the tumor cells were positive for vimentin and muscle actin. Together with ultrastructural findings of intracytoplasmic microfilaments with focal densities and profiles of well-developed, rough endoplasmic reticulum, these features reinforced the conclusion of myofibroblastic or smooth muscle differentiation of the tumor cells. One of the tumors was analyzed by flow cytometry and was shown to be DNA diploid. The present report provides clinicopathological findings of the first two Japanese cases of intranodal myofibroblastoma.

A clinicopathologic and immunohistochemical review was made of seven cases of angiomyofibroblastoma. The patients were middle-aged women who had a slowly growing mass, measuring 1.5-6 cm in maximum dimension, located subcutaneously in the vulva. The tumors were well-demarcated and characterized by well-vascularized, alternating hypercellular and hypocellular edematous areas composed of bland, plump spindle- or oval-shaped stromal cells frequently aggregated around small blood vessels. An epithelioid appearance of the stromal cells was seen in two cases. Immunohistochemically, the stromal cells were consistently positive for vimentin and desmin, but negative for muscle specific actin, alpha-smooth muscle actin, myosin, cytokeratins, S-100 protein or von Willebrand factor. Ultrastructurally, the plump stromal cells had a small amount of peripherally located rough endoplasmic reticulum, numerous pinocytotic vesicles and abundant intermediate filaments, on which immunogold probes for desmin were localized, whereas fine filaments were few and there were no electron dense plaques. Thus, while the proliferating stromal cells expressed an immunohistochemical profile of peculiar myoid differentiation, ultrastructural findings differed from those of smooth muscle cells or those seen in typical myofibroblasts. At 1-4 years after surgery, there was no evidence of recurrence.

We report a rare occurrence of cardiomyopathy associated with allergic bronchopulmonary aspergillosis (ABPA). A 49-year-old man with a history of bronchial asthma was referred to the Matsuyama Red Cross Hospital for evaluation of the abnormal shadow on his chest X-ray. Laboratory examination showed blood eosinophilia and marked elevation of serum IgE concentration and IgE antibody to A fumigatus. The immediate and late skin reactivities to A fumigatus antigen were both positive. The diagnosis of ABPA was made. Treatment using prednisolone was effective in ameliorating the symptoms. However, he was admitted again due to dyspnea, edema and anorexia 6 months later. Chest X-ray, ECG, UCG and scintigraphy suggested severe cardiac failure. The clinical diagnosis of hypertrophic cardiomyopathy, and the pathohistological diagnosis of endomyocardial fibrosis were made by cardiac catheterization and biopsy of endocardium. Retrospectively, cardiomegaly had gradually increased during the past several months while peripheral blood eosinophilia had continued. All these data strongly suggested that eosinophilia due to ABPA might cause severe cardiac damage.

A clinicopathologic study of 18 cases of fibroma of tendon sheath included an immunohistochemical survey of 7 cases and an electron-microscopic examination of one. The age of the patients ranged from 1 to 77 years, with a median of 34 years. The most common site of the tumors was the finger (7 cases), followed by the knee (3), the hand (2), and the foot (2). The median greatest diameter of the tumor was 2 cm. The tumors were attached or closely related to the tendon or tendon sheath, and usually well circumscribed, and multinodular or lobulated. Microscopically, spindle or stellate tumor cells with fuchsinophilic cytoplasm were embedded in a dense fibrous stroma with scattered small blood vessels. Most tumor cells have immunoreaction products for actin in the cytoplasm with accentuation along the cell membrane. Ultrastructurally, many of the tumor cells proved to be myofibroblasts.

A rare case of granular cell tumor of the gallbladder in a 58-year-old Japanese man is presented. This is the third report of such a tumor arising in the gallbladder. The immunohistochemical study demonstrated the localization of the nervous-system-specific protein (S-100 protein) in the granular component cells, thereby supporting the Schwann cell origin of this tumor.

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.

A clinicopathologic and immunohistochemical review was made of 24 cases of distinctive nerve sheath tumors located in the gastrointestinal tract. The tumors were microscopically evident in the presence of peripheral lymphoid cuffing and benign nuclear atypia. The tumors arose in the muscularis propria of the stomach in 23 cases and in the ascending colon in 1 case. The patients included 9 men and 15 women whose ages ranged from 36 to 78 years (average, 58). No recurrence has developed in any patient who underwent resection. Although positive immunostaining for S-100 protein, Leu 7 antigen, and laminin might support the schwannian nature of these tumors, the positive immunoreactivity for glial fibrillary acidic protein (GFAP) indicated the possibility of a myenteric plexus origin. The pattern of S-100 protein immunostaining differed from that seen in cases of gastrointestinal stromal tumors associated with von Recklinghausen's neurofibromatosis or that noted in cases of conventional leiomyomas. We propose that these tumors be designated as benign schwannoma of the gastrointestinal tract.

Twenty-nine cases of malignant schwannoma consisted of three groups; 11 tumors associated with von Recklinghausen's disease (group I), nine tumors arising grossly from nerve trunks (group II), and 11 tumors so diagnosed basically on the histologic features (group III). Using the immunoperoxidase methods, the tumors were investigated with regard to S-100 protein, keratin, and epithelial membrane antigen (EMA). Approximately one-third of the cases (10 of 29) were devoid of S-100 positive cells and the remaining two-thirds (19 of 29) contained positive cells, with variable frequencies. The number of S-100 positive cells differed, depending largely on the presence or absence of neurofibroma-like areas in the tumor. The positive cells were rarely found in the group III tumors, which were neither associated with von Recklinghausen's disease nor connected to nerve trunks, even when their histologic features were unequivocal. Certain specific organoid structures in the tumor, such as neuroid or tactoid ones, were positive for S-100 protein. In one of the two malignant epithelioid schwannomas, the tumor cells were strongly positive for S-100 protein, thereby suggesting melanocytic differentiation. This tumor was interpreted as a melanocytic malignant schwannoma rather than a malignant melanoma, based in part on the fact that the overlying epidermis was uninvolved in this patient with von Recklinghausen's disease. True epithelial differentiation in one case of glandular schwannoma was verified by the positive stain of EMA along the inner surface of the glandular element.

The presence and distribution of S-100 protein were studied in 63 cases of liposarcoma and 20 cases of myxoid malignant fibrous histiocytoma (MFH), using the immunoperoxidase technique. Normal adipose tissue and benign lipomatous tumours were also studied by the same technique, for purposes of comparison. In all liposarcomas, most of the adipocytes and vacuolated lipoblasts were positive for S-100 protein, although the tumour cells in non-lipogenic areas of dedifferentiated liposarcoma and the non-vacuolated giant cells with a deeply eosinophilic cytoplasm in the pleomorphic liposarcomas were devoid of S-100 protein immunoreaction products. One third of the myxoid type liposarcomas contained numerous immunoreactive, immature-appearing spindle or oval cells, reminiscent of the primitive fat organs of white adipose tissue. Conversely, none of the myxoid MFHs contained S-100 protein in the tumour cells, including the irregularly vacuolated ones. These results suggests that the immunohistochemical demonstration of S-100 protein is a useful diagnostic tool, particularly for the assessment of vacuolated tumour cells and for the diagnosis of myxoid tumours.

Cytologic examination of ascitic fluid from a patient with an ovarian adenosquamous carcinoma revealed both adenocarcinoma cells and squamous carcinoma cells. This is believed to be the first report of such a case.

Histological and immunohistochemical studies of a granular cell tumor involving the lower lid are described. Histological examination showed it to have typical features of a granular cell tumor. Nervous-system-specific protein (S-100 protein) was detected in both the nuclei and cytoplasm of granular cells using the peroxidase-anti-peroxidase method. This result further supports the concept of the neurogenic origin of granular cell tumors.

This clinicopathologic study concerns 8 cases of extraskeletal Ewing's sarcoma, including electron-microscopic examination of one case. In three patients, autopsy was done. The age of the patients ranged from 12 to 31 years with a median of 16 years. The tumors mainly arose in the soft tissues of the trunk (4 cases) and the lower extremity (3 cases). Histologically, they were made up of closely packed uniform, small cells, arranged in sheets separated by strands of fibrovascular stroma. The tumor cells had round to oval nuclei with finely dispersed chromatin and scanty ill-defined cytoplasm almost invariably containing a fair amount of diastase-digested PAS-positive material. Ultrastructurally, the tumor cells were composed principally of undifferentiated mesenchymal cells, and contained prominent pools of glycogen in the cytoplasm. Aggregates of intermediate filaments were seen in a perinuclear location. These light- and electron-microscopic findings are indistinguishable from those of Ewing's sarcoma of the bone. Differential points from other soft-tissue small round cell sarcomas such as malignant neuroepithelioma (peripheral neuroblastoma), embryonal or alveolar rhabdomyosarcoma were briefly discussed.

Five round cell neoplasms of the soft parts that histologically resembled malignant rhabdoid tumors of the kidney were studied. The tumors were composed mainly of poorly differentiated round or, sometimes, polygonal cells, with a minority of elongated cells; the cytoplasm of many of the cells contained filament-laden acidophilic inclusions. Ultrastructurally, the intracytoplasmic structures were seen to consist of aggregates of 10-nm intermediate filaments, and immunohistochemical staining revealed the presence of cytokeratin and vimentin. All five patients with this tumor had an aggressive clinical course; three of the patients died shortly after the initial diagnosis. As this tumor does not seem to be linked to any known entity, it is referred to as malignant rhabdoid tumor of the soft parts and could be a heterogeneous entity.

Clinicopathologically we studied the autopsy cases including 110 soft tissue sarcoma (28 malignant fibrous histiocytomas, 23 rhabdomyosarcomas, 18 leiomyosarcomas, 11 liposarcomas, 7 synovial sarcomas, 4 angiosarcomas, 3 malignant schwannomas, and 16 others) and 29 malignant bone tumors (19 osteosarcomas, 3 Ewing's sarcomas, 3 chondrosarcomas, and 4 others). We may summarize as follows: (1) In autopsy cases sarcomas occurring in the retroperitoneum outnumbered those in surgical cases in frequency, probably because most retroperitoneal tumors could not be removed and were difficult to diagnose without the help of autopsy findings. (2) Metastases were disclosed most often in the lungs, followed by the bones and liver. Lymph-node metastases were also encountered more frequently than expected, particularly in rhabdomyosarcoma (48%) and synovial sarcoma (57%). (3) Transition in histologic features, including cellular differentiation, nuclear grade and cellularity, from the surgically resected tumors to the tumors at autopsy in the same case, occurred not infrequently.

This clinicopathologic study concerns 19 cases of malignant hemangiopericytoma among 755 cases of soft tissue sarcomas. The age of the patients ranged from 18 to 76 years, with a median of 43 years. Tumors occurred on the trunk in 8, lower extremities in 5, the head in 3, and the retroperitoneum in 3. According to follow-up information, nine of the 19 patients had died. Histologically the tumor was characterized by its homogeneous vascular pattern, its uniform cell population and a wide range of cellular anaplasia. After extensive sampling of the tumors, a comparative light microscopy revealed differences in diagnostic histology between malignant hemangiopericytoma and other soft tissue sarcomas with a hemangiopericytoma-like vascular pattern. The frequency of appearance of such pericytoma pattern in different soft tissue sarcomas was as follows: 4/4 cases (100%) in extraskeletal mesenchymal chondrosarcoma, 11/14 (79%) in infantile fibrosarcoma, 27/45 (60%) in synovial sarcoma, 62/201 (30%) in malignant fibrous histiocytoma, 9/37 (25%) in malignant schwannoma and 6/72 (8%) in liposarcoma.

Renal cell carcinoma in children is extremely rare compared to Wilms tumor. We report on a 7-year-old Japanese boy with left renal cell carcinoma. Since the disease was clinical stage I, nephrectomy with tumor extirpation was performed after a short course of initial chemotherapy had been administered. The patient is free of disease 3 years postoperatively. In a review of the Japanese literature we found 71 reports of renal cell carcinoma in children less than 15 years old. Mean patient age at occurrence was 8.1 years, there were no differences in regard to the sex or the affected side, and the most frequent symptom was the presence of a mass. We stress the early establishment of diagnosis in children with a persistent abdominal mass, hematuria and flank pain, since surgical treatment leads to a favorable prognosis only in the early stage of renal cell carcinoma.

We report the occurrence of rhabdoid cells in several specified soft tissue sarcomas of round cell variety. The rhabdoid cells had an acidophilic cytoplasm containing a globular perinuclear inclusion and were characterised ultrastructurally by the presence of aggregates of 10 nm intermediate filaments. These filaments contained both cytokeratin and vimentin, as demonstrated immunohistochemically. Extensive sampling of soft tissue sarcomas revealed the presence of such cells in different types of soft tissue round cell sarcomas as follows: 12 of 13 cases of epithelioid sarcomas, 8 of 13 synovial sarcomas (composed predominantly of round cells), 6 of 20 extraskeletal myxoid chondrosarcomas and 4 of 4 round celled malignant mesotheliomas. We wish to stress that the appearance of rhabdoid cells is not a monopoly of one particular type of tumour.

Five solitary, benign, soft-tissue tumors histologically resembling infantile myofibromatosis but which occurred in adults were found among more than 5,000 benign soft-tissue tumors from a tumor registry. The tumors clinically presented as superficial, painless, and slowly enlarging nodules, usually of more than 10 years' duration, that occurred in the upper (two cases) and lower (two cases) extremities or the buccal mucosa (one case). They developed in the dermis and subcutis as well-circumscribed nodules with an average diameter of 1.2 cm. They were composed of discrete and confluent fibrous tissue with a mixture of bundles of smooth muscle-like cells and a hemangiopericytoma-like area of immature mesenchymal cells. Immunostaining for actin and intermediate filaments revealed the myofibroblastic nature of the tumor cells. The tumors were surgically excised, and there has been no recurrence. Clinicians and pathologists should note that the lesion of infantile myofibromatosis can and does occur in adults.