Cytology of papillary solid-cystic neoplasm of the pancreas presenting as an extrapancreatic mass: a case report.

BACKGROUND: Papillary solid cystic neoplasm (PSCN) of the pancreas is a tumor of low malignant potential and has an excellent prognosis. Although the cytologic features are well documented, it can pose a diagnostic problem when it presents as an extrapancreatic mass. CASE: A young woman presented with a retroperitoneal mass. Sonography and computed tomography (CT) showed a partially cystic mass touching the spleen and pancreas but distinct from both organs. The CT-guided aspiration cytologic diagnosis was paraganglioma. At surgery the mass was attached to the tail of the pancreas by a pedicle. The histologic diagnosis was PSCN of the pancreas. CONCLUSION: The cytologic findings in paraganglioma and PSCN may be strikingly similar, with both showing a perivascular pattern, acinar formations, cells with a moderate amount of ill-defined cytoplasm with red granularity on May-Grunwald Giemsa stain and a uniform chromatin pattern. This may be a source of diagnostic error, particularly in a patient presenting with a retroperitoneal, extrapancreatic mass.