Nonmucinous Cystic Neoplasm of the Pancreas with Ovarian-like Stroma

A 50-year-old woman was admitted to our hospital for close examination of an enlarging pancreatic cyst. CT and MRI showed a 55-mm cyst with a thin wall in the tail of the pancreas without an apparent mural nodule. The pancreatic parenchyma was normal and there was no dilatation of the main pancreatic duct. Endoscopic ultrasonography showed a 45-mm cyst with a thin wall and no septations. The cyst had two 5-mm mural cysts ([Fig. 1]). There was no apparent blood flow in the mural cysts on color Doppler imaging. The main pancreatic duct was 2 mm in diameter without dilatation, and the rest of the pancreatic parenchyma had no abnormality. There was no apparent communication between the pancreatic duct and the cyst. The cyst was initially diagnosed as mucinous cystic neoplasm, based on age, sex, location, and imaging findings. For a definitive diagnosis and treatment, the patient underwent laparoscopic distal pancreatectomy. Grossly, the cyst had a thin uniform wall, a smooth inner surface, and small mural cysts (6 mm) ([Fig. 2]). The cyst contents were serous. Pathological findings showed that the cyst epithelium was lined with a single layer of nondysplastic cuboidal cells with no mucus. Beneath the epithelium was a layer composed of spindle cells resembling ovarian stroma. For the immunohistochemistry finding, the ovarian-like stroma was positive for progesterone receptor ([Fig. 3]). The final diagnosis was nonmucinous cystic neoplasm of the pancreas with ovarian-like stroma. This is a rare case of benign pancreatic cystic neoplasm, mimicking the imaging findings of mucinous cystic neoplasm.

Fig. 1 Endoscopic ultrasonography showed a 45-mm cyst with a thin wall with no septations. The cyst had two 5-mm mural cysts.

Fig. 2 Grossly, the cyst had a thin uniform wall, a smooth inner surface, and small mural cysts.

Fig. 3 Pathological findings showed that the cyst epithelium was lined with a single layer of nondysplastic cuboidal cells with no mucus. Beneath the epithelium was a layer composed of spindle cells resembling ovarian stroma. For the immunohistochemistry finding, the ovarian-like stroma was positive for progesterone receptor.

Publication History

Article published online:
27 July 2021