Combined Mohs Micrographic Surgery in a Collision Tumor

Abstract

We present the case of a 73-year-old male patient with a collision tumor in the right ear, consisting of a basal cell carcinoma and melanoma in situ. He was managed with Mohs micrographic surgery combining paraffin-embedded sections and frozen sections. Multiple surgical stages were required to obtain tumor-free margins. The surgical defect was reconstructed by plastic surgery, achieving the preservation of the ear. The technique of combining two processing sections is useful in the treatment of the collision of basal cell carcinoma with malignant melanoma.

Hepatocellular carcinoma‑cavernous hemangioma collision tumor: A case report

“…A collision tumor consists of two independent tumors of different cell lineages that occur very close to each other in the same body area or organ; however, a clear boundary between the two tumor types is maintained ( 1 , 2 ). The pathogenesis of collision tumors has not been thoroughly investigated and remains uncertain.…”