title: [Soft tissue clear cell sarcoma. Morphology, differential diagnosis and tumor classification].
abstract: Clear cell sarcomas of tendons and aponeuroses were first described by Enzinger in 1965 and are characterized by the occurrence in young adults, frequent location in the distal lower extremity and slow, but often relentless clinical course. The histologic features of 5 own cases are presented, the cellular arrangement in nest-, cluster- or "ball"-like formations and a prominent nucleolus are emphasized as most reliable diagnostic patterns. Some aspects of differential diagnosis are discussed, especially those concerning its histologic distinction from fibrosarcomas, malignant melanomas, malignant Schwannomas and synovial sarcomas. The electron microscopic examination of one case revealed findings which may be considered as typical for tumors developed from neural crest derived cells: envelopment of many tumor cells by basal lamina-like structures, specialized cellular contacts, interdigitations of cellular processes and "wrapping around"-phenomena (so-called mesocollagen formation). Some neurosecretory granules (not described till now in clear cell sarcomas) and fibrous long spacing collagen further support the suggestion that clear cell sarcomas pertain to the group of tumors with relationship to neuroectodermal cells and tissues. We feel that, because of their typical histologic picture and their particular clinical behavior, they should not be regarded as malignant (soft tissue) melanomas or malignant (melanotic) Schwannomas but retained as a defined clinico-pathological entity.
mesh_terms: D000328:Adult; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007866:Leg; D008297:Male; D008545:Melanoma / Q000175:diagnosis / Q000473:pathology; D008854:Microscopy, Electron; D008875:Middle Aged; D012509:Sarcoma / Q000175:diagnosis / Q000473:pathology*; D012983:Soft Tissue Neoplasms / Q000175:diagnosis / Q000473:pathology*
vernacular_title: Das Klarzellsarkom des Weichgewebes. Morphologie, Differentialdiagnose und Tumoreinordnung.