Malignant melanoma of the esophagus complicated with poorly differentiated mucinous adenocarcinoma of the stomach: A case report

RATIONALE: Primary malignant melanoma of the esophagus (PMME) is a rare malignancy that only accounts for <2% of all primary esophageal tumors. Here, we report the even rarer occurrence of PMME in combination with poorly differentiated mucinous adenocarcinoma of the stomach. PATIENT CONCERNS: A 64-year-old man was presented to the hospital with >1 month of eating dysphagia. Enhanced computed tomography (CT) scan only found a space-occupying lesion in the lower esophagus with moderate enhancement. However, gastroscope showed not only esophageal masses, but also gastric mucosa changes. DIAGNOSES: Poorly differentiated mucinous adenocarcinoma and PMME were diagnosed based on pathological biopsy and immunohistochemical methods. INTERVENTIONS: The patient underwent laparoscopic gastric cancer radical surgery, esophageal resection, and colonic replacement of the esophagus. OUTCOMES: Abdominal CT and esophagography performed 1 week after surgery showed that it was consistent with postoperative changes without other abnormalities. However, the patient died 3 months after discharge without receiving any other treatment. LESSONS: This case suggests more attention should be drawn to the diagnosis of multiple primary malignant neoplasms in elder patients, and also highlights the need to fulfill comprehensive examinations before surgery in case of misdiagnosis. Besides, it is challenging to finding a reasonable treatment for such rare condition.