Neuroendocrine Transdifferentiation in Cutaneous Melanoma: A Case Report and Review of the Literature. (17th April 2023)

• Record Type: Journal Article
• Authors: Pisani, David; Micallef, Daniel; Scerri, Jeanesse; Betts, Alexandra; Degaetano, James; Baldacchino, Shawn
• Is Part Of: American journal of dermatopathology. Volume 45:Number 4(2023)
• Page Start: 264
• Page End: 268
• Publication Date: 2023-04-17
• Subjects: melanoma -- neuroendocrine -- transdifferentiation -- in-transit metastasis -- small cell carcinoma -- INSM1 -- CD56 -- synaptophysin; Skin -- Diseases -- Periodicals; Histology, Pathological -- Periodicals; 616.50705
• DOI: 10.1097/DAD.0000000000002377
• Languages: English
• ISSNs: 0193-1091

Abstract

Abstract: Neuroendocrine transdifferentiation refers to the progressive transformation of a nonneuroendocrine tumor to the one showing evidence of neuroendocrine differentiation on morphological and immunohistochemical grounds. Although this phenomenon has been well-documented in certain malignancies, particularly prostatic adenocarcinoma after androgen deprivation, cases of neuroendocrine transdifferentiation in melanomas are exceptionally rare. Herein, we report a case of a conventional superficial spreading melanoma occurring on the skin of the leg in a young male which showed progressive neuroendocrine transdifferentiation as it progressed through 2 in-transit metastases and a nodal metastatic deposit over a 4-year period. The tumor retained the BRAF V600E mutation throughout the disease process, and disease control was achieved through dual BRAF inhibition therapy. The possibility of melanoma masquerading as a high-grade neuroendocrine malignancy when investigating tumors of unknown primary should be kept in the mind of clinicians and histopathologist alike as a potential diagnostic pitfall, thus helping avoid misdiagnosis and guide appropriate treatment strategies.