Rare Upper Mediastinal Oligometastasis from Early Esophagogastric Adenocarcinoma: A Case Report

Esophagogastric junction (EGJ) adenocarcinoma is an aggressive cancer with poor prognosis. Metastasis to the upper mediastinal lymph nodes is rare, with reported rates of 3.8% to 6.1%. This case report highlights the diagnostic and therapeutic challenges of oligometastatic recurrence in EGJ adenocarcinoma, emphasizing the role of surgery in selected cases.

A 63-year-old male underwent proximal gastrectomy for a Siewert type 2 poorly differentiated EGJ adenocarcinoma. Postoperative histopathology confirmed the diagnosis of stage 1 cancer. At 30 months, contrast-enhanced computed tomography (CT) scan detected a right paratracheal lymph node recurrence. Subsequent follow-up CT and positron emission tomography (PET) scan revealed progressive enlargement of the same lymph node with negative PET uptake. Owing to strong clinical and radiological suspicion of oligometastasis, thoracoscopic lymphadenectomy was performed with the patient in the left lateral decubitus position under one-lung ventilation. The postoperative histopathological examination confirmed metastatic adenocarcinoma. The patient was discharged uneventfully on postoperative day 5 and prescribed with adjuvant tegafur-gimeracil-oteracil (S-1). He remained asymptomatic during ongoing surveillance.

This case highlights the challenges in diagnosing oligometastatic recurrence of EGJ adenocarcinoma, particularly when typical imaging signs are absent. It also demonstrates the importance of a multidisciplinary treatment approach, including careful surveillance and timely intervention. Surgery is one of the options for oligometastasis.