Serous Cystadenoma of the Pancreas: Potentials and Pitfalls of a Preoperative Cytopathologic Diagnosis.

Objective: Pancreatic serous cystadenomas (SCAs) are benign tumors. Technological advances in imaging have led to increased recognition of asymptomatic pancreatic cysts, consequently increasing the demand for cytomorphologic evaluations of cyst fluid.

Methods: A retrospective search through the pathology archives over an 11-year period was performed to identify SCAs from pancreatectomy specimens with a presurgical pancreatic EUS-guided fine-needle aspiration (FNA).

Results: Fifty-one FNAs were identified. The average patient age was 59.9 years and 34 (67%) were female. Thirty-five (69%) of the SCAs were located in the body or tail of the pancreas. SCAs ranged in size from 1.3 to 8.0 cm (mean 4.9). On imaging, features suggestive of SCA were seen in 7 (14%) cases. The cytologic diagnoses were as follows: SCA in 5 (10%) cases, suspicious for mucin-producing neoplastic cyst in 4 (8%), pseudocyst in 4 (8%), and benign ductal and/or acinar epithelium, not otherwise specified in 24 (47%). Additionally, 14 (27%) cases were deemed nondiagnostic.

Conclusions: A cytopathologic diagnosis of SCA on FNA is extremely difficult. The salient cytomorphologic features for identifying SCAs included scant cellularity, a mostly clear background, absence of extracellular mucin, hemosiderin-laden macrophages, and loose fragments of cuboidal cells with a notable absence of necrosis, atypia, and mitoses.