Hematoxylin-eosin staining of the biopsy specimen revealed a papillated, thickened, and markedly pigmented epidermis with an increased number of mature sebaceous lobules of various sizes and shapes in the reticular dermis. The side of the biopsy specimen corresponding to the area of clinical change contained a cystlike space marked by papillations lined by 2 layers of cells, the luminal side of which revealed decapitation secretion consistent with apocrine differentiation. Within the fronds of stroma created by the papillations is an infiltrate of plasma cells.
A Pigmented Verrucous Plaque on the Cheek—Diagnosis. Arch Dermatol. 2004;140(11):1393-1398. doi:10.1001/archderm.140.11.1393-b