REPORT OF A CASE
A 2-year-old male child had been seen with an isolated papular lesion on his posterior neck that had been present since birth. The lesion consisted of seven waxy erythematous oval papules in a linear distribution on the nape below the hairline (Fig 1).A diagnosis of epidermal nevus was considered because of the linearity of the lesion. Molluscum contagiosum was also entertained, because some of the papules had a central umbilication. One papule was treated with liquid nitrogen, but, when it failed to involute, a biopsy was performed. On microscopic examination, the epidermis showed a central invagination lined by two cell layers with the formation of villi. The stroma contained an infiltrate of plasma cells, neutrophils, and histiocytes (Figs 2 and 3).At the age of 6 years, the child returned, because the papules had increased in size and number and were now pruritic (Fig 4).
Goldberg NS, Esterly NB. Linear Papules on the Neck of a Child. Arch Dermatol. 1985;121(9):1199-1200. doi:10.1001/archderm.1985.01660090113028