A 52-year-old white woman presented with a pruritic, scaly lesion on her right forearm that had been present for several months. Her medical and family histories were unremarkable.
The physical examination revealed a 5×6-mm, well-circumscribed, erythematous plaque on the dorsal aspect of the right forearm (Figure 1). The lesion was treated twice with cryosurgery and subsequently with diflorasone diacetate cream, but persisted despite these measures. A 4-mm punch biopsy specimen of the lesion revealed epidermal hyperplasia with compact hyperkeratosis and acanthosis. In the stratum spinosum and granulosum, there were vacuolar and granular changes with coarse, prominent keratohyaline granules. The dermis showed prominent solar elastosis (Figure 2).
Pereyo NG, Sangueza OP, Davis LS. Persistent, Solitary, Erythematous, Hyperkeratotic Plaque. Arch Dermatol. 1998;134(4):499-504. doi:10.1001/archderm.134.4.499