Medallion-like dermal dendrocyte hamartoma: a case misdiagnosed as neurofibroma.

Medallion-like dermal dendrocyte hamartoma is a rare congenital lesion, comprised of a benign dermal proliferation of fusiform cells that stain positive for CD34, often positive for factor XIIIa, and negative for S100. It has a highly characteristic clinical presentation consisting of a well-circumscribed atrophic and wrinkled patch located on the upper trunk or neck that remains stable with time. We report a case of an 11-year-old boy with a typical medallion-like dermal dendrocyte hamartoma on the nape of the neck that was previously misdiagnosed as neurofibroma on the basis of initial histological examination that was later reevaluated due to lack of clinical correlation. Three previously-reported cases of medallion-like dermal dendrocyte hamartoma also have had a previous histological misdiagnosis of probable neurofibroma; other reported cases have been misdiagnosed as congenital atrophic dermatofibrosarcoma protuberans. Clinical correlation and immunostaining are particularly important for the recognition of this rare benign lesion.