Histopathologic examination of the specimen showed a highly cellular ulcerated tumor limited to the dermis. There was a dense, chaotic arrangement of atypical plump spindle-shaped cells, pleomorphic round or polyhedral cells with abundant eosinophilic cytoplasm, and mononucleated or multinucleated giant cells, often with bizarre nuclei. Mitoses were numerous and sometimes abnormal. The stroma was scarce, with a discrete inflammatory infiltrate. The tumor was limited to the superficial and middle dermis and contiguous to an unaffected epidermis. There was no vascular or lymphatic invasion. Immunohistochemical stains were positive for CD68 and negative for HMB-45, melan-A, S100 protein, CD31, CD34, and cytokeratin. The diagnosis of AFX was made. Treatment consisted of surgical excision, with a margin of 15 mm because of the unusually large size of the tumor, followed by skin graft.
Burgeoning Nodule on the Scalp of a 65-Year-Old Man—Diagnosis. Arch Dermatol. 2007;143(5):653-658. doi:10.1001/archderm.143.5.653-g