REPORT OF A CASE
A previously healthy, 50-year-old white man presented with a 2-year history of a slowly expanding, nonhealing plaque on the vertex of his scalp. The patient related that the lesion started to develop soon after he sustained an injury to the area when he hit his head against a trailer. He did not give a history of other skin or medical problems. He had used no topical or oral medications and had no known allergies. On examination, there was a 2.5×2.0-cm plaque with friable scale and a surrounding rim of erythema on the vertex of the scalp (Figure 1).The rest of the scalp was normal. There was no evidence of other skin, mucosal, or nail lesions, and there was no lymphadenopathy. A shave biopsy specimen was obtained from an edge of the lesion and stained with hematoxylin-eosin (Figure 2 and Figure 3).What is your diagnosis?
Egan CA, Zone JJ. An Isolated Scaling Plaque on the Scalp. Arch Dermatol. 1997;133(10):1307-1308. doi:10.1001/archderm.1997.03890460131019