Atypical fibroxanthoma with prominent sclerosis.
BACKGROUND
Malignant cutaneous spindle cell lesions with marked sclerosis are uncommon. Only a few cases of cutaneous leiomyosarcoma and dermatofibrosarcoma protuberans with sclerosis have been published.


METHODS
We report a case of atypical fibroxanthoma (AFX) with prominent sclerosis and hyalinization occurring on the scalp of an 81-year-old male.


RESULTS
Histopathologic examination revealed an exophytic, well-delineated, focally ulcerated tumor arising in sun-damaged skin. The lesion was composed of atypical spindle cells arranged in a fascicled and vaguely storiform pattern. Occasional multinucleated giant cells were present. The tumor cells were strongly positive for CD99 (O13), vimentin, and smooth muscle actin, and focally positive for CD68. There was striking sclerosis with hyalinization throughout the lesion.


CONCLUSIONS
Rarely, AFX may exhibit marked sclerosis with areas of complete replacement of tumor by hyalinized collagen. In a small biopsy, such hyalinization may be a diagnostic pitfall leading to an erroneous diagnosis.
Bruecks
Andrea K
AK
Calgary Laboratory Services, University of Calgary, Calgary, AB, Canada. andrea.bruecks@cls.ab.ca
Medlicott
Shaun A
SA
Trotter
Martin J
MJ
D000368:Aged; D000369:Aged, 80 and over; D006258:Head and Neck Neoplasms / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D018219:Histiocytoma, Benign Fibrous / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D006801:Humans; D006818:Hyalin / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D009381:Neoplasms, Radiation-Induced / Q000473:pathology; D012535:Scalp; D012598:Sclerosis / Q000150:complications / Q000378:metabolism / Q000473:pathology; D012878:Skin Neoplasms / Q000737:chemistry / Q000150:complications / Q000473:pathology*; D013472:Sunlight / Q000009:adverse effects