Adenocarcinoma Arising in an Esophageal Duplication Cyst With Disseminated Metastases: A Rare Case Detected on 18F-FDG PET/CT.

Esophageal duplication cysts (EDCs) are rare congenital anomalies resulting from aberrant development of the posterior division of the primitive foregut. Malignant transformation of EDCs is exceptionally rare, with only a limited number of cases reported in the literature. The most commonly described histologic type in these transformations is adenocarcinoma. Herein, we report a case of an incidentally detected adenocarcinoma in an EDC with systemic metastases at initial presentation, in a patient with elevated tumor markers and strong clinical suspicion of underlying malignancy on 18F-FDG PET/CT.