Atypical Fibroxanthoma with Granular Cell Change

Abstract

Atypical fibroxanthoma is a fairly common dermal neoplasm that is characterized histologically by infiltrating pleomorphic spindle cells and atypical giant cells with numerous mitoses. Clinically, the lesion most commonly presents as a solitary ulcerated papule on the head or neck of elderly males. We report a patient with a rare granular cell variant of atypical fibroxanthoma. The patient was a seventy‐five‐year‐old male with a history of squamous cell carcinoma on the left scalp treated by Mohs surgery two years prior. In the vicinity of the previous squamous cell carcinoma site, the patient presented with a slow growing, approximately 1.0 by 1.0 cm red, violaceous, firm nodule on the left scalp. The clinical impression was recurrent squamous cell carcinoma. Biopsy of the lesion revealed a dermal tumor composed of pleomorphic cells with eosinophilic granular cytoplasm with numerous typical and atypical mitoses. The tumor stained focally with Factor VIII, CD 68, and SMA and 30% of the neoplastic cells stained with Ki 67. Staining for Keratin cocktail, High Molecular Weight Keratin, Melan A and S100 were negative. PAS strongly stained the granules. These features are consistent with a granular cell variant of atypical fibroxanthoma.