Gastric Duplication Cyst Revealed After an Endoscopic Ultrasound-Guided Fine-Needle Aspiration of a Suspected Mucinous Cystadenoma of the Pancreas

Gastrointestinal duplication is a rare congenital anomaly of the gastrointestinal tract. Gastric duplication cysts (GDCs) are uncommon in adults, and most cases are discovered incidentally. Here, we report a fortuitous discovery of a rare case of an asymptomatic noncommunicating GDC in an adult revealed after an endoscopic ultrasound-guided fine-needle aspiration of a suspected mucinous cystadenoma of the pancreas. A 34-year-old female presented with renal colic. Her abdominal examination was normal. She presented a cystic image at the left lumbar discovered fortuitously during ultrasonography. On uro-computed tomography, there was a suspicion of a pancreatic cystadenoma. Magnetic resonance imaging of the pancreas suggested a mucinous cystadenoma of the pancreatic tail. The endoscopic ultrasound showed a cystic thick-walled formation in the tail of the pancreas. After guided fine-needle aspiration, a split aspect of the gastric wall appeared evoking a GDC. The cytology showed epithelial cells without mucin. Three years later, the patient does not have any gastrointestinal symptoms. GDCs are a rare anomaly, and accurate diagnosis of these cysts is difficult. Surgical resection can offer a definitive diagnosis. The mainstay of treatment is surgery to avoid the risk of malignancy.