Cellular benign fibrous histiocytoma. Clinicopathologic analysis of 74 cases of a distinctive variant of cutaneous fibrous histiocytoma with frequent recurrence.
We report seventy-four cases of a distinctive variant of cutaneous fibrous histiocytoma, which is often mistaken histologically for sarcoma and which carries a high local recurrence rate. These tumors appeared most commonly in young or middle-aged adults, with a predominance in men (male/female ratio 1.9:1). Anatomic distribution was wide, with cases occurring mainly in the upper limb/limb girdle (34%), lower limb/limb girdle (27%), and head and neck region (20%). Most lesions had been present for only a few months, and their sizes ranged from 0.5 cm to 2.5 cm in maximum diameter. Twelve (26%) of 46 cases with follow-up (mean duration 3 years) recurred locally, in one case twice. Distinctive histologic features were a commonly fascicular growth pattern, predominance of eosinophilic spindle cells with tapering nuclei, a moderate mitotic rate (mean three per 10 high-power fields), and frequent extension into the subcutaneous fat (33% of cases). In addition, all cases showed at least focal cytologic polymorphism (inflammatory cells, foam cells, giant cells), and 58% showed associated epidermal alterations in common with usual cutaneous fibrous histiocytomas. Nine cases (12%) showed foci of central necrosis. Immunohistochemical studies (ABC method) found only vimentin and very focal smooth muscle actin positivity. Tests for CD34, desmin, S-100, keratin, and Factor XIIIa were negative in all cases. These lesions should be distinguished from dermatofibrosarcoma protuberans and leiomyosarcoma, with which many of these cases were initially confused.
Department of Histopathology, St Thomas's Hospital (U.M.D.S.), London, England.
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Calonje
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Mentzel
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Fletcher
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D005260:Female; D018219:Histiocytoma, Benign Fibrous / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007150:Immunohistochemistry; D007223:Infant; D008297:Male; D008875:Middle Aged; D008938:Mitosis; D009364:Neoplasm Recurrence, Local; D012878:Skin Neoplasms / Q000378:metabolism / Q000473:pathology*