Primary malignant melanoma of esophagus following chemoradiotherapy for esophageal squamous cell carcinoma: report of a case

Primary malignant melanoma of the esophagus (PMME) is a rare neoplasm. We observed a case of PMME that had occurred at an irradiated site in the thoracic esophagus. The patient was a 74-year-old man who had received definitive chemoradiotherapy for esophageal squamous cell carcinoma at the age of 68, and had completely recovered. Six years later, via periodic upper gastrointestinal endoscopy, he had been diagnosed with esophageal tumors. After the patient underwent esophagectomy, the removed esophageal tumors were immunohistologically diagnosed as PMME, and most of the tumor was observed to be located within the irradiated area corresponding to the previous radiotherapy. The patient has been free of recurrence and metastasis and alive for 20 months after the second surgery without any additional treatment. The clinical course of this patient suggests that therapeutic radiation may be a factor in the occurrence of PMME.