Supplementary Material for: Primary malignant melanoma of the esophagus treated with surgical resection at an early stage.

Introduction
Primary malignant melanoma of the esophagus is a very rare disease with a poor prognosis. We herein report a patient with primary malignant melanoma of the esophagus who underwent surgical resection.
Case presentation
A 73-year-old female underwent an upper gastrointestinal endoscopy during follow-up for colonic diverticulitis. An endoscopic examination and constructed radiography revealed a slightly elevated black pigmented lesion in the upper esophagus and a black pigmented area in the esophagogastric junction. Through a preoperative endoscopic biopsy, she was diagnosed with malignant melanoma of the esophagus. We performed thoracoscopy-assisted and laparoscopy-assisted subtotal esophagectomy with lymphadenectomy. The surgical specimens were subjected to immunohistochemical analysis, resulting in a diagnosis of malignant melanoma. The tumor cells were positive for Melan-A and HMB45 diffusely, supporting that diagnosis. We performed surgical resection in a case of primary malignant melanoma of the esophagus, and the patient has remained disease-free for 2 years since the surgery.
Conclusion
Early diagnosis during and radical resection may be essential for long-term survival in patients with malignant melanoma of the esophagus.