Cutaneous Neoplasms Composed of Melanoma and Carcinoma: A Rare but Important Diagnostic Pitfall and Review of the Literature
We report two cases of combined cutaneous tumors composed of melanoma and carcinoma. The first tumor presented as a 5-mm pink-blue macule over the right zygomatic arch in an 85-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of melanoma (highlighted by SOX10 and MART-1, with high Ki-67 proliferative index) intermixed with nodular basal cell carcinoma (highlighted by pan-cytokeratin and Ber-EP4). The neoplastic melanocytes were confined to the basal cell carcinoma nodules, and a diagnosis of combined melanoma in situ and basal cell carcinoma was rendered. After therapeutic excision, the patient was disease-free at 9 months after the initial diagnosis. The second tumor presented as a 6-mm pink-brown crusted papule on the right forehead in an 89-year-old man. Shave biopsy and immunohistochemical studies revealed that the tumor was composed of malignant melanoma (MM) (highlighted by S100 and MART-1) intermixed with squamous cell carcinoma (SCC) (highlighted by cytokeratin and p63), and a diagnosis of combined MM-SCC was rendered. These two cases highlight the importance of recognizing these rare types of melanocytic-epithelial cutaneous neoplasms to arrive at an accurate diagnosis that may inform appropriate disease stage and therapy.
Mejbel, Haider A.; Nelson, Kelly C.; Pradhan, Dinesh; Ivan, Doina; Zaleski, Michael; Nagarajan, Priyadharsini; Tetzlaff, Michael T.; Curry, Jonathan L.; Torres-Cabala, Carlos A.; Prieto, Victor G.; and Aung, Phyu P.. 2020. Cutaneous Neoplasms Composed of Melanoma and Carcinoma: A Rare but Important Diagnostic Pitfall and Review of the Literature. Journal of Cutaneous Pathology. Vol.47(1). 36-46. https://doi.org/10.1111/cup.13551 PMID: 31361351 ISSN: 0303-6987