S3417 Solid Pseudopapillary Neoplasm of the Pancreas Masquerading as Irritable Bowel Syndrome

Introduction: Solid pseudopapillary neoplasm (SPN) of the pancreas is a rare malignant tumor that represents less than 3% of all pancreatic neoplasms. We present a case of a 24-year-old woman with persistent atypical abdominal symptoms found to have SPN. Case Description/Methods: A 24-year-old woman presented to our emergency department with abdominal pain in her left upper quadrant radiating to the back. She reported a 2-year history of intermittent pain accompanied by bloating, constipation, and diarrhea, previously attributed to irritable bowel syndrome (IBS). An outpatient computed tomography scan identified a 3.5 cm complex cystic lesion in the pancreatic tail. Subsequent MRCP further characterized the lesion as a 3.5 × 3.7 cm T2 hyperintense, T1 hypointense, heterogeneously enhancing cystic mass with nodular enhancing components abutting the adjacent stomach and causing a mild mass effect. Endoscopic ultrasound (EUS) revealed a complex 3.7 cm cystic lesion in the tail of the pancreas, adjacent to the spleen, without evidence of ductal obstruction. Using Doppler guidance, a 19-gauge needle was used to aspirate blood-tinged fluid and cyst wall cells for diagnostic analysis. Fluid analysis showed a carcinoembryonic antigen (CEA) level of 1.3 ng/mL, amylase of 118 U/L, and glucose of 66 mg/dL. PancraGEN testing indicated benign features. Cytology demonstrated papillary cell proliferation with relatively uniform nuclei and fibrovascular cores. Immunostaining was positive for pancytokeratin (partial), CD10, progesterone receptor (PR), and CD56, with occasional intracytoplasmic PAS-positive globules consistent with a solid pseudopapillary neoplasm of the pancreas. Ultimately, she underwent a laparoscopic distal pancreatectomy with splenectomy. Discussion: SPN are rare malignant tumors that mainly affect young women. Although often asymptomatic, they may present with nonspecific symptoms, posing a diagnostic challenge. In our case, the patient’s initial symptoms mimicked IBS. Even though SPN generally have a low metastatic potential, a minority may exhibit aggressive behavior, underlining the importance of early surgical resection, which is associated with a good prognosis. This case highlights the importance of maintaining a broad differential diagnosis for persistent and/or atypical abdominal symptoms in young women, even when initial findings suggest a functional etiology, as earlier recognition is critical to ensure timely treatment.