Atypical Fibroxanthoma

An ulcerating nodule on his left pre-auricular region worried a 64-year-old man. Drs Charles E. Crutchfield III and Humberto Gallego of St Paul identified the lesion as an atypical fibroxanthoma, a spindle cell tumor. These lesions commonly erupt on older adults. Sun-exposed areas, such as the nose, ear, and cheek regions, are usual sites.

Atypical fibroxanthomas generally appear as solitary or ulcerated nodules that measure less than 2 cm in diameter. However, they can enlarge rapidly. When these lesions arise on the extremities, they may be larger and more invasive.

Consider squamous cell carcinoma, basal cell carcinoma, ulcerated cysts, and pyogenic granuloma in the differential diagnosis. Confirm the diagnosis with dermatopathologic evaluation.

An atypical fibroxanthoma is a superficial form of malignant fibrous histiocytoma. These lesions usually follow a benign course, but fatal malignancies have occurred. Because of the risk of malignancy and the strong possibility of recurrence, surgical excision with margin control is recommended. Moh's micrographic surgery removed this patient's lesion, which did not recur.