Atypical fibroxanthoma of the skin. A clinicopathologic study of 140 cases

In an attempt to further understand the nature of atypical fibroxanthoma of the skin, 140 lesions were subjected to clinical, histologic, and histochemical studies. Atypical fibroxanthoma most commonly presented as a solitary, nonspecific nodule or ulceronodule on exposed skin of the face in the elderly. A clinical variant occurred in much younger persons on the covered areas of the trunk and limbs. Histologically, atypical fibroxanthoma develops as a circumscribed, cellular proliferation within the dermis, with occasional infiltration into the subcutis. Morphological patterns vary from lesions showing plump spindle cells in interlacing fascicles to those with haphazardly arranged large polyhedral cells. Bizarre multinucleated giant cells with foamy cytoplasm and numerous mitotic figures enhance its distrubing sarcoma-like appearance. Among 101 patients followed for periods up to 15 years, no metastatic lesions were found and only nine lesions recurred. Correlation of the clinical and follow-up data support the concept that in spite of its alarming histologic appearance, atypical fibroxanthoma of skin appears to behave in a benign manner.