REPORT OF A CASE
A 24-year-old black man with a schizoaffective disorder treated with lithium, benztropine mesylate (Cogentin), and haloperidol (Haldol) had poliosis overlying a nontender, firm nodule on the right parietal scalp since birth. This flesh-colored, slightly lobulated plaque (4×4 cm) superimposed with terminal hairs, the majority of which were white, was present on the right parietal scalp (Figure 1). The skull roentgenogram revealed only frontal bossing. An endocrinologic workup, which consisted of human growth hormone and somatomedin-C levels, was normal.Sections of a punch biopsy specimen from the scalp nodule are shown (Figures 2 and 3).What is your diagnosis?
Congenital intradermal nevus with poliosis.
Examination of hematoxylin-eosin-stained sections of a punch biopsy specimen from the scalp nodule showed perifollicular dermal nests of melanin-pigmented round cells (Figure 2). The S100 stain showed absence of both melanin and melanocytes within the hair follicles as well
Mendez B, Wood C. Poliosis in a Scalp Nodule. Arch Dermatol. 1993;129(10):1336. doi:10.1001/archderm.1993.01680310107022