Ciliated foregut cyst of the pancreas: preoperative diagnosis using endoscopic ultrasound guided fine needle aspiration cytology--a case report with a review of the literature.

A 51-year-old male presented with a 4-month history of abdominal pain, decreased appetite, and postprandial bloating. A CT scan showed a solitary, 5.3 x 4.4 cm, cystic lesion in the body/tail of the pancreas. Endoscopic retrograde cholangiopancreatography did not show communication between the pancreatic duct and the cystic lesion. Endoscopic ultrasound (EUS) examination revealed a 6.9 x 2.4 cm cystic lesion in the body/tail region of the pancreas without septae or solid components. The pancreatic parenchyma, pancreatic duct, and common bile duct were unremarkable. EUS-guided fine needle aspiration (EUS-FNA) was performed using a 22-gauge EchotipTM needle. Only a few drops of viscous fluid could be aspirated. Papanicolaou-stained direct smears and SurePath (Autocyte) preparations were evaluated. The direct smears were hypocellular; however, the concentration method producing liquid-based cytology preparation showed detached ciliary tufts (degenerated debris with ciliated cellular fragments of cell tops without nuclei) and occasional intact ciliated cells consistent with a ciliated foregut cyst. Although benign, the cyst was resected to alleviate the symptoms. The surgical pathology confirmed the benign preoperative interpretation of the ciliated foregut cyst. To the best of our knowledge, this is the first case of pancreatic ciliated foregut cyst reported to be diagnosed preoperatively by EUS-FNA. For a proper preoperative cytologic diagnosis, the needle rinses should be processed adequately. Otherwise, these hypocellular specimens with mucin may be misinterpreted as mucinous cystic lesions.