This 59-year-old woman developed a papule on her forehead. The clinician submitted this as a nevus. Sebaceous hyperplasia is a benign proliferation of sebaceous glands, often on the face, and often submitted to rule out a nevus or a basal cell carcinoma. Calling this a neoplasm is generous as it typically consists of a few extra sebaceous lobules (usually >3) forming a mass. Although not necessarily a biologic continuum, one can argue a histologic continuum to sebaceous adenoma, "epithelioma" diagnosed by some authors, and sebaceous carcinoma as the proportion of basaloid cells, mitoses, and atypia increases. We will diagnose sebaceous hyperplasia when the clinician clearly biopsied a mass, there are abundant sebaceous lobules, and no malignancy is identified. This is a typical clinical and histologic example of this entity.
Histologic sections of skin show a proliferation of sebaceous lobules, forming a nodular configuration. The lesion is well-circumscribed and consists of bland, mature-appearing sebocytes. The basaloid cells are confined to the periphery of the lobules.