Clinical history: Rapidly growing ulcerated lesion on the scalp of a 70 year old man.
What is the diagnosis, and what familial syndrome may be associated with this?
Atypical Fibroxanthoma (AFX)
AFX is usually a benign lesion, considered to be a pseudomalignancy due to its worrisome histologic features including atypia, bizarre cells and frequent mitoses. Architecturally it is usually well circumscribed, non-encapsulated, highly cellular and centered in the dermis. Three cell types may be present, including plump spindle cells, large polyhedral cells, and giant cells, which can be floridly pleomorphic and bizarre. The histologic appearance is similar to that of malignant fibrous histiocytoma.
Immunohistochemistry is positive for vimentin and negative for cytokeratin and EMA, which can be used to distinguish it from squamous cell carcinoma and melanoma.
Sporadic lesions are common on the head and neck of elderly, and are associated with sun exposure. It may be found in children with xeroderma pigmentosum