Melan-A expression in non-melanocytic carcinoma: A potential diagnostic pitfall

• Linwei Zuo ^[1] ; Huiyan You ^[1] ; Zhe Cai ^[1] ; Shousheng Liao ^[1] ; Xiangtong Lu ^[1] ; Lixiang Li ^[1] ; Wenyong Huang ^[1]
  1. [1] Second Affiliated Hospital of Nanchang University

     Second Affiliated Hospital of Nanchang University

     China

     
• Localización: Histology and histopathology: cellular and molecular biology, ISSN-e 1699-5848, ISSN 0213-3911, Vol. 39, Nº. 8, 2024, págs. 1037-1041
• Idioma: inglés
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• Resumen

  • Background. Melan-A/MART-1 is a melanocytic differentiation marker recognized as an antigen on melanoma cells. It is a useful diagnostic marker for pathologists in the diagnosis of melanocytic tumors. However, we recently found that Melan-A can be expressed in some non-melanocytic carcinomas that are rarely reported in the literature.

    Methods. We analyzed the expression of Melan-A in 87 non-melanocytic carcinoma tissue samples by immunohistochemistry. Marker positivity was defined as ≥10% positive tumor cells.

    Results. In 87 non-melanocytic carcinoma tissue samples, Melan-A was positive in six (6.89%) cases, of which four (66.7%) were male and two (33.3%) were female, with a mean age of 60 years (range 21-82 years).

    Five (83.3%) of the Melan-A-positive cases had distant metastases. Compared with Melan-A negative cases, Melan-A positive non-melanocytic carcinomas were significantly associated with poor prognosis (P=0.0023).

    Conclusions. Melan-A expression is relatively rare in non-melanocytic carcinoma cases. This report highlights a potential diagnostic pitfall in the diagnosis of melanoma, urges pathologists to exercise caution in cases of Melan-A positivity, and illustrates the need for an immunohistochemical marker panel to avoid misdiagnosis.