To the Editor.—
In the November 1984 Archives, Mehregan and Plotnick1 reported the case of a young black man with xeroderma pigmentosum who developed a keratoacanthoma. Histologic examination disclosed "numerous deeply pigmented and highly dendritic melanocytes" among the proliferating keratinocytes. The authors commented that the simultaneous proliferation of melanocytes and keratinocytes is more or less a frequent phenomenon in many slow-growing epidermal and adnexal tumors. In the case reported of a rapidly growing lesion, the authors hypothesized that the unusual high rate of melanocyte proliferation "may be due to the underlying genetic abnormality of cells in this black patient with xeroderma pigmentosum." We have recently seen two similar cases in white patients with no genetic abnormalities. Hence, we must search for another explanation for this reactive proliferation of melanocytes.
Report of Cases.—Case 1.—
A 73-year-old man with a fair complexion and blue eyes presented with a nodule of
Sanchez-Yus E, Gonzalez-Moran A. Proliferation of Melanocytes in Keratoacanthoma. Arch Dermatol. 1985;121(8):968-969. doi:10.1001/archderm.1985.01660080022006