Pleomorphic and atypical multinucleated giant cells in solid pseudopapillary neoplasm of pancreas: A diagnostic pitfall in cytology and a review of the literature

Solid pseudopapillary neoplasm of the pancreas (SPN) is a rare low-grade malignancy typically occurring in young women. Occasionally, these neoplasms present with pleomorphic to atypical multinucleated giant tumor cells which may mimic high-grade malignancy. Our patient is a 25-year-old male who presented with one year of intermittent epigastric pain. Magnetic resonance imaging showed a 3.1 × 2.5 cm mass in the pancreas body. Endoscopic ultrasound-guided fine needle aspiration of the mass showed large pleomorphic cells and atypical multinucleated giant cells in a background of singly scattered polygonal cells. Focally, these cells surrounded delicate hyalinized to fibrovascular cores forming pseudopapillae. Immunohistochemical stains show tumor cells are positive for beta-catenin, CD10, vimentin, and CD56. Although rare surgical pathology publications have described the presence of pleomorphic to atypical multinucleated giant cells occurring in SPN, to our knowledge, this is the first case reported example focused on cytomorphologic illustration and description.