Rare primary malignant melanoma of the esophagus with gastric cardia adenocarcinoma: A case report.

RATIONALE: This case report presents an unusually rare instance of primary malignant melanoma of the esophagus (PMME) occurring concurrently with gastric cardia adenocarcinoma. It emphasizes diagnostic pitfalls in amelanotic melanoma and provides evidence supporting the role of adjuvant radiotherapy in achieving prolonged disease-free survival for this aggressive malignancy. PATIENT CONCERNS: A 60-year-old male with chronic tobacco and alcohol use presented with a 2-week history of progressive dysphagia. Endoscopy identified an obstructive esophageal mass and a gastric cardia ulcer, initially misdiagnosed as poorly differentiated carcinomas due to the absence of melanin pigmentation. DIAGNOSES: The patient received a diagnosis of PMME in conjunction with gastric cardia adenocarcinoma. INTERVENTIONS: Transthoracic esophagectomy with lymphadenectomy followed by adjuvant radiotherapy (5000 cGy/DT/25F) targeting the surgical bed and regional lymphatics. OUTCOMES: No recurrence or metastasis was observed over 7 years posttreatment, surpassing typical survival outcomes for PMME. LESSONS: Amelanotic PMME poses significant diagnostic challenges due to its resemblance to poorly differentiated carcinoma, necessitating immunohistochemical confirmation (S-100, HMB-45, Melan-A). This case highlights the potential survival benefit of combining surgery with adjuvant radiotherapy in PMME, contrasting with historical outcomes in cases managed by surgery alone. Clinicians should maintain a high index of suspicion for synchronous malignancies in high-risk patients, particularly those with chronic carcinogen exposure. Emerging therapies, including immune checkpoint inhibitors targeting programmed cell death-1/CTLA-4 or NF-1 mutation-driven pathways, warrant exploration in PMME management. The unique lymph node metastasis pattern underscores the importance of comprehensive nodal sampling and tailored adjuvant strategies in dual-primary malignancies.