Atypical fibroxanthoma

Abstract

20522 We report on 15 patients who were diagnosed and treated with atypical fibroxanthoma in the Department of Dermatology Minden since 1994. The patients were between 35 and 85 years old with a mean age of 69.9 years. Of the 13 males and 2 females solitary tumours were observed at the ear in 5 patients, at the capillitium in 5 patients, in the face in 3 patients and in the shoulder/axilla area in 2 patients. The lesion were 0.5 to 15 mm in size and half of them ulcerated in severely damaged actinic skin. Histologically, the tumours showed pleomorphic histiocyte proliferation and atypical giant cells often with bizarre nuclei and numerous mitotic figures. Immunohistologically, the tumours were vimentin positive and HMB45, S100, keratin, desmin, EMA, CD34, and actin negative. The clinical evaluation showed no metastatic lesions. The tumours were treated by radical surgery and followed up every half year. The mean observation time is now 24 months without any recurrence. The atypical fibroxanthoma was first reported in 1963 by Helwig. Nowadays, it is thought to be a low grade malignancy as the superficial variant of malignant fibrous histiocytoma. Important is that this tumour follows an indolent behaviour but locally an aggressive course. Small numbers of metastases have been reported. The differential diagnoses includes dermatofibrosarcoma protuberans, malignant melanoma, spindle-cell squamous cell carcinoma and other rare tumour entities The clinical picture should be known not to underestimate this fibrous histiocytic neoplasm as a benign lesion. No significant financial relationships to disclose.