Fig. 3
a CT showed a 1.5-cm cyst with a septum at the time of detection (a). Preoperative CT showed a 2.4-cm low-density cystic tumor in the tail of the pancreas in all phases and showed a septum (b, c). b Magnetic resonance imaging showed a low-intensity T1 signal and high-intensity T2 signal in the tumor (arrow), and the connection between the pancreatic duct and cystic tumor could not be detected by magnetic resonance cholangiopancreatography. c Endoscopic ultrasound showed a thickened cell wall in the cyst (arrow). d (a) Resected specimen and cyst content. (b) Microscopy showed no ovarian-like stroma and epithelial cells lined by a single layer of cuboidal pancreato-biliary cells (arrow). However, the stromal cells expressed an estrogen receptor and a progesterone receptor. The epithelial cells showed no expression of MUC1, 2, 5AC, and 6, which showed that the tumor had an ovarian-like stroma but not MUC secretion. No malignant and invasive lesion was found. CT computed tomography, MUC mucin