Masquerading tumors of abdomen – a rare case of retroperitoneal bronchogenic cyst

Background Bronchogenic cysts are congenital foregut anomalies predominantly mediastinal or pulmonary. Retroperitoneal localization is exceedingly rare, with fewer than 50 cases reported worldwide. They are often misdiagnosed as Gastro-Intestinal Stromal Tumors (GISTs) or as lymphatic cysts. This case highlights the diagnostic pitfalls and emphasizes the importance of histopathological confirmation in the diagnosis of retroperitoneal bronchogenic cysts. Case presentation A 68-year-old lady with diabetes and asthma presented with postprandial abdominal discomfort and regurgitation for 2 months. Imaging revealed an exophytic growth arising from the lesser curvature of the stomach, initially suspected as GIST. Surgical excision was performed, and histopathology confirmed it to be a bronchogenic cyst lined by ciliated pseudostratified columnar epithelium with cartilaginous elements. Conclusion Retroperitoneal bronchogenic cysts (RBCs) are rare but should be considered in the differential diagnosis of retroperitoneal cystic lesions. This case underscores these tumors as a diagnostic mimic and highlights the role of a high index of suspicion and the role of histopathology for definitive diagnosis. Complete surgical resection remains curative.