Seventeen cases of malignant melanoma of soft parts (clear cell sarcoma) are reported. The patients ranged from 9 to 70 years of age, but 13 were between 10 and 40 years of age. There were eight male patients and nine female patients. The most common tumor location (seven patients) was the foot, followed by the area around the knee (four patients). The usual histologic pattern was that of variably sized nests of uniform plump spindle cells with clear to pale cytoplasm separated by fine to coarse fibrous septa; however, variants with a substantial proportion of epithelioid cells, moderate to marked nuclear pleo-morphism, predominantly diffuse growth, or a microcystic pattern were seen. Patient survival was relatively poor overall (median, 49 months; ten deaths due to tumor) and was determined mainly by distant metastasis (11 patients). Both survival and distant metastasis were correlated with tumor size (P < 0.01 for patients with tumors z 5 cm versus < 5 cm). Other clinical and pathologic factors, including patient age, sex, and race, tumor location, duration of symptoms, initial therapy, mitotic rate, tumor necrosis, proportion of epithelioid cells, and nuclear pleomorphism had no significant relation to survival or distant metastasis when tumor size was taken into account. Local recurrence and regional lymph node metastasis each occurred in four patients. Cancer 65:367-374. 1990. ALIGNANT MELANOMA of soft parts was reported M originally under the title clear cell sarcoma often-dons and aponeuroses by Enzinger' in 1965. Subsequently , it became apparent that this tumor was in fact a soft tissue melanocytic n e ~ p l a s m , ~-~ and Chung and Enzinger' changed its name to malignant melanoma of soft parts in 1983. There have not been many series published of more than a few cases of malignant melanoma of soft parts, and prognostic factors have received little attention. Therefore, we reviewed cases of malignant melanoma of soft parts and evaluated possible prognostic factors. Materials and Methods Cases filed at our institution as malignant melanoma of soft parts (clear cell sarcoma) were reviewed. (A few earlier cases had been filed as synovial sarcoma and identified in the course of a previous study of that entity.) Criteria for the inclusion of a case in the study were that the diagnosis be confirmed, that clinical information and From the *

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Twenty-six ependymomas were studied by light and electron microscopy. By electron microscopy, the acellular zones around small vessels in light microscopic sections were seen to be composed of large numbers of closely packed, filament-rich, cytoplasmic processes ringing small vessels. Lumina were consistently present but many of them were too small to be seen by light microscopy. The lumina contained slender, curving microvilli and variable numbers of cilia. Their bordering cells were connected by unusually long tight junctions. Electron microscopy can be useful to establish or confirm a diagnosis of ependymoma when the light microscopic appearance is atypical, or when the tumor arises in an unusual location. The clinical data on the 26 cases has been reviewed; follow-up information was available on 23 patients.

Peripheral neuroepitheliomas should be included in the differential diagnosis of a soft-tissue tumor in the extremities or chest wall, especially in young adolescents. MRI provides useful information as to the extent of the tumor and relationship with adjacent structures, although it may not differentiate neuroepitheliomas from other, more common, soft-tissue sarcomas. Together with clinical and histological findings, MRI can assist in the diagnosis and treatment planning of this tumor.