Dermatopathology (Jul 2021)

A Wolf in Sheep’s Clothing: Collision of Melanoma and Keratoacanthoma

  • Matthias Walther,
  • Sandra Falkvoll,
  • Sebastian Leibl

DOI
https://doi.org/10.3390/dermatopathology8030030
Journal volume & issue
Vol. 8, no. 3
pp. 253 – 257

Abstract

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Collision tumors consisting of melanoma and squamous cell carcinoma are very rare. We present the case of a deceptive hyperkeratotic nodule on the forearm of a 72-year-old woman, which clinically appeared to be a squamous cell carcinoma, keratoacanthoma type. Histological examination surprisingly revealed a coexisting epithelioid melanoma. Thus, this case report shows the importance of an early histopathological and immunohistochemical workup to prevent unnecessary diagnostic and therapeutic delay with negative effects on prognosis.

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