Abstract:

Primary malignant melanoma of the esophagus (PMME) is an extremely rare malignant tumor. To investigate its clinicopathological characteristics, this study reports the clinicopathological features, immunophenotypes, and prognostic information of two cases. The patients were a 74-year-old female and a 64-year-old male, who presented with a foreign body sensation during swallowing and abdominal distension, respectively, with no history of primary melanoma in the skin or other sites. The lesions were located in the upper and lower esophagus, and appeared grossly as a large ulcer and a slightly elevated nodule, respectively. Microscopic examination revealed localized loss of the surface squamous epithelium in both cases, with in situ melanoma components observed within the residual epithelium. Immunohistochemical analysis demonstrated that tumor cells in both cases strongly expressed melanoma antigen recognized by T-cells 1 (MelanA) and SRY-box transcription factor 10 (Sox-10), with partial expression of S100 calcium-binding protein (S100) and microphthalmia-associated transcription factor (MiTF). This study indicates that PMME is a rare primary esophageal tumor whose endoscopic appearance can easily be confused with those of other primary esophageal malignancies. Therefore, pathological diagnosis plays a crucial role in establishing the diagnosis of this disease.

Key words: primary malignant melanoma of the esophagus (PMME), pathological diagnosis, immunophenotype