Macrocystic serous cystadenoma of the pancreas.

We report a 47-year-old woman with macrocystic serous cystadenoma of the pancreas. She had no past history of abdominal surgery, instrumentation, or trauma. Ultrasonography and computed tomography revealed a unilocular cyst in the body of the pancreas. On magnetic resonance imaging, the cyst showed heterogeneous signal intensity on T1-weighted images, and was homogeneously hyperintense and oligolocular is on T2-weighted images. A preoperative diagnosis of mucinous cystic neoplasm of the pancreas was made, and distal pancreatectomy was performed. The resected oligolocular cyst was 5.0 x 4.5 x 3.0 cm and was lined with a single layer of cuboidal epithelium similar to that seen in microcystic serous cystadenomas. Abundant glycogen was demonstrated within the epithelial cells, as assessed by periodic acid-Schiff (PAS) staining with and without diastase digestion. The cyst exhibited a gross appearance distinct from that of typical microcystic adenomas, resulting in diagnostic difficulties for the radiologists and surgeon involved in the patient's care.