Since Castellani's original communication,1 cases have been reported by Castellani and Duval.2 Michael and Seale3 and myself.4 Furthermore, many observers (Wise,5 Fox,6 MacKee7 and others) have since recalled having seen similar cases previous to Castellani's report in 1925, which they, at that time, had diagnosed as flat warts, tiny nevi and a host of other clinical entities.
Castellani2 noted that "numerous black or dark brownish papules, somewhat cupoliform or at times flattened, are seen on the face, principally on both malar regions ; while they are usually rare or absent on the lower parts of the face and chin, a few may be present on the forehead." Michael and Seale3 enlarged this clinical concept and established, as a result of their microscopic studies, the nosologic position by showing that the lesion is a nevus, characterized histologically by an irregular, noninflammatory acanthosis
DIASIO FA. DERMATOSIS PAPULOSA NIGRA (CASTELLANI) OF UNUSUAL DISTRIBUTION(ACANTHOSIS PAPULOSA NIGRA). Arch Derm Syphilol. 1933;27(5):751–755. doi:10.1001/archderm.1933.01450040760004