Yoshiyuki Fujii

Epithelioid angiosarcoma of bone

Angiosarcoma of bone is a rare, high-grade sarcoma of vascular origin. This article describes an epithelioid angiosarcoma in the humerus of a 48-year-old man. A multilocular osteolytic lesion with undefined margins and destroyed cortical and medullary bone, associated with a large soft tissue mass was demonstrated radiologically in the proximal metaphysis of the right humerus. The tumor, resected by amputation, was composed mostly of proliferating malignant cells with an epithelioid morphology. It had a predominantly sheet-like growth pattern, and an occasional pseudoglandular or alveolar arrangement, mimicking an adenocarcinoma. The dilated anastomotic vascular spaces lined by epithelioid endothelial cells and the intracytoplasmic lumina/vacuoles that sometimes contained erythrocytes suggested focal endothelial differentiation. On immunohistochemical investigation, many neoplastic cells expressed cytokeratin and endothelial markers: factor-VIII related antigen, CD31, and UEA-I. The ultrastructure of the tumor was consistent with that of an angiosarcoma. Our patient died of disease shortly after the diagnosis, implying an aggressive clinical course. Awareness of the existence of skeletal epithelioid angiosarcoma, combined with the identification of intracytoplasmic lumina, or at least small vasoformative foci, and immunohistochemical positivity for endothelial markers provide the best guide for distinguishing this tumor from metastatic carcinomas.

Adenocarcinoma arising from a mature cystic teratoma of the testis

Abstract A 52‐year‐old male diagnosed pathologically with metastatic adenocarcinoma of the skin was referred to our department. Physical examination revealed a right scrotal mass the size of childs head and several skin tumors. Right high orchiectomy and resection of skin tumors were performed. Histopathological examination revealed a well‐differentiated, mucinous adenocarcinoma originating from the gastrointestinal epithelium in a mature cystic teratoma (dermoid cyst) of the testis and metastatic mucinous adenocarcinoma of the skin. We made a diagnosis of teratoma with malignant transformation (TMT) of the testis. Combination chemotherapy with low‐dose cisplatin/5′‐deoxy‐5‐fluorouridine (CDDP/5′‐DFUR) was initiated, but the patient died 8 months after orchiectomy. At autopsy, similar mucinous adenocarcinoma of the testis and the skin were observed at the metastatic sites.

Undifferentiated carcinoma of the vulva mimicking epithelioid sarcoma.

We report an undifferentiated sweat gland carcinoma of the vulva in an 80-year-old woman. The tumor, which was located in the right labium majus, resembled an epithelioid sarcoma histologically; it had a granulomatous appearance with multiple tumor nodules containing epithelioid tumor cells. The tumor also contained rhabdoid cells; a large cluster of them showed histological features indistinguishable from those of a malignant rhabdoid tumor. Immunohistochemically, the tumor cells reacted not only for epithelial markers such as cytokeratins, EMA, and CEA, which are known to be expressed by epithelioid sarcoma, but also for CA125 and with monoclonal antibodies recognizing sweat gland structures--namely, EKH5 and EKH6. For comparison, two epithelioid sarcomas and two extrarenal malignant rhabdoid tumors were also studied. Of these tumors, only one extrarenal rhabdoid tumor reacted with EKH5, and none reacted for CA125. Electron-microscopic examination of the present tumor showed the presence of discontinuous basal laminae and tonofibril-like structures as well as primitive cell junctions and interdigitating filopodia. From these findings, we conclude that the tumor was an undifferentiated sweat gland carcinoma mimicking an epithelioid sarcoma. Findings in this case support the idea of the diverse histogenesis of extrarenal malignant rhabdoid tumors and indicate that electron microscopy is important for differentiating epithelioid sarcoma from skin adnexal carcinoma.

Immunohistochemical Study of Fiber Types in Human Extraocular Muscles

Fiber types in human extraocular muscle (h‐EOM) were examined immunohistochemicaliy with antibodies against slow tonic (anti‐ALD) and slow twitch (anti‐SOL) myosins. Four types of muscle fiber in h EOM were distinguishable according to their reactivities with these antibodies. Groups 1 and 2 fibers reacted with both antibodies, group 1 fibers showing stronger reactivity than group 2 fibers with anti‐ALD. Group 3 fibers reacted only with anti‐SOL. Group 4 fibers did not react with either antibody. The latter were the most common, and were the main fibers in both the peripheral (outer orbital) and central zones of h EOM. The next most common were group 1 fibers, which were located mainly in the peripheral layer. Group 2 fibers were less common, but were the second most common type in the central layer. Group 3 fibers were only minor constituents. Multiple innervations were observed in some fibers of groups 1 and 2, and group 1 fibers were suggested to be slow tonic myofibers in h‐EOM. These specific immunohistochemical and physiological features of h‐EOM seem to be the basis of the low morbidity seen in the usual types of muscular dystrophy. Acta Pathol Jpn 40: 808‐814, 1990.

Cat scratch disease: an epidemiological and ultrastructural study of lymphadenitis caused by Warthin-Starry positive bacteria

The aetiological agent of cat scratch disease (CSD) has been unknown for more than 30 years. Recently, a micro-organism clearly shown with Warthin-Starry silver (W-S) stain was found and thought to be a possible cause of the disease. In this study, 32 cases of regional lymphadenopathy histologically compatible with CSD and 20 contrasting cases of lymphadenopathy were examined retrospectively with W-S stain. W-S positive pleomorphic organisms were clearly demonstrated in 20 of the 32 suspected cases of CSD, but in none of the other cases. The onset of disease in these 20 cases with W-S positive organisms occurred between July and January. This seasonal variation in the onset of disease was highly significant (P<0.005) and was not due to a single epidemic. Moreover, some characteristic morphological features of the organism were found by electron microscopic observations. Ultrastructurally, the organism was a bacterium showing a chain-like arrangement, septal formation, branching and clubbed ends.The aetiological agent of cat scratch disease (CSD) has been unknown for more than 30 years. Recently, a micro-organism clearly shown with Warthin-Starry silver (W-S) stain was found and thought to be a possible cause of the disease. In this study, 32 cases of regional lymphadenopathy histologically compatible with CSD and 20 contrasting cases of lymphadenopathy were examined retrospectively with W-S stain. W-S positive pleomorphic organisms were clearly demonstrated in 20 of the 32 suspected cases of CSD, but in none of the other cases. The onset of disease in these 20 cases with W-S positive organisms occurred between July and January. This seasonal variation in the onset of disease was highly significant (P less than 0.005) and was not due to a single epidemic. Moreover, some characteristic morphological features of the organism were found by electron microscopic observations. Ultrastructurally, the organism was a bacterium showing a chain-like arrangement, septal formation, branching and clubbed ends.

Retroperitoneal schwannoma is characterized by a high incidence of cellular type and GFAP-immunoreactivity.

To clarify the clinicopathologic characteristics of retroperitoneal schwannomas, which are sometimes confused with other spindle cell tumors, 27 cases were studied microscopically and immunohistochemically. The 27 cases consisted of 17 females and 10 males, the ages of whom ranged from 31–79 (mean 57.4) years. Gross examination revealed well‐demarcated, encapsulated tumors, 3–15 cm (mean 8 cm) in diameter. Microscopic review divided them into 13 cases of cellular/fascicular, 3 of conventional, 6 of intermediate, and 5 of ancient type. Cellular/fascicular schwannomas were composed of cellular fascicles of spindle cells, in which nuclear palisading, Antoni B area and cyst were unclear, while numerous foamy cells were intermingled. Immunohistochemical investigation revealed diffuse, strong positivity for S‐100 protein and Sox10 in all tumors studied. In addition, glial fibrillary acidic protein (GFAP) was extensively expressed in 92% of the cellular/fascicular type, while it was less prominent in others. The present study suggests that retroperitoneal schwannoma often occurs in the middle‐aged woman, grows to a large size, exhibits cellular/fascicular microscopic features in half of the cases, and may arise from GFAP‐positive Schwann cells. The presence of hyalinized vessels and dense infiltration of foamy macrophages as well as diffuse immunoreactivity for S‐100 protein and Sox10 are helpful for the differential diagnosis.

Morules with optically clear nuclei in ovarian borderline endometrioid tumor

Optically clear nuclei (OCN) have been observed in morules of some neoplasms and in some conditions unrelated to the development of the morules. We first report a case of ovarian borderline endometrioid tumor (BET) showing the morules associated with OCN. The patient was a 47‐year‐old premenopausal woman with a left ovarian cystic tumor, atypical endometrial hyperplasia, and elevated serum levels of FSH, LH, estradiol, and CA 125. The resected ovarian tumor measured 6 cm in diameter, and showed a papillary growth. Histologically, the ovarian tumor was consistent with BET, and the morules with OCN were scattered. Immunohistochemically, OCN were proven to be rich in biotin. An aberrant nuclear expression of beta‐catenin was observed in both the tumor cells and the morular cells. Our case may suggest the possibility that the appearance of OCN with or without morules in ovarian tumors is related to endometrioid differentiation of the tumor cells, and should be recognized as a diagnostic clue of ovarian endometrioid tumors. Although female sex hormones have been reported to play a role in the occurrence of OCN, the participation of beta‐catenin mutation has also been suggested.

Pseudosarcomatous myofibroblastic tumor of the urinary bladder with massive intraperitoneal hemorrhage in a child

Abstract A 3‐year‐old boy presented with persistent abdominal pain, hematuria and facial pallor with progressive anemia. A computed tomography scan showed a massive intraperitoneal hemorrhage and tumor mass in the bladder. Histological examinations of the resected tumor revealed findings of pseudosarcomatous myofibroblastic tumor (PMT). The clinico‐pathological features of this case warn us that PMT can cause acute abdomen syndrome with massive intraperitoneal hemorrhage.