S1448 Solid Pseudopapillary Neoplasm of Pancreas: A Rare Pancreatic Malignancy

Abstract

INTRODUCTION: Solid pseudopapillary neoplasm of pancreas (SPN) is one of the rarest types of pancreatic tumors, <2% of all pancreatic malignancies, also known as a Hamoudi or Frantz tumor. SPNs usually presents asymptomatically in females in the third decade of life and found incidentally on radiological imaging. CASE DESCRIPTION/METHODS: Here, we present three proven SPN cases by histology. Case 1: A 42-year-old Hispanic female with no past medical history who presented with 1-day history of cough, incidentally found to have a 3 cm hypodense lesion in the pancreatic body on CT scan. Endoscopic ultrasound (EUS) with biopsy was performed and immunohistochemical (IHC) studies found tumor cells to be positive for B-catenin, progesterone receptor and neuron specific enolase, consistent with a diagnosis of SPN. Case 2: A 48-year-old African American female with a past medical history of GERD presented with intermittent right upper quadrant abdominal pain. CT demonstrated a large solid, periportal hepatic mass (19 × 17 × 19 cm) as well as a multi-cystic mass (14 × 7 × 10 cm) arising from the distal pancreatic tail. Exploratory laparotomy was performed and pathology showed a uniform population of small cells with pseudopapillary structures with IHC profile supporting the diagnosis of metastatic SPN. Case 3: A 31-year-old Hispanic female with no significant past medical history presented with 2 months history of post-prandial epigastric abdominal pain found to have a hypodense mass (4 × 4 cm) in the distal pancreatic tail. Surgical resection was performed. Pathology findings of neoplastic tumor cells with occasional groves, collections of histiocytes, and hyaline globules with positive IHC staining for vimentin, B-catenin and progesterone receptor, consistent with diagnosis of SPN. DISCUSSION: On imaging, SPN tumors typically appear as a well-defined mass, with a thick, enhancing capsule, often with peripheral or central calcification. Although most often solid, they can demonstrate variable internal hemorrhagic or cystic components. EUS is the modality of choice for further imaging and definitive diagnosis, as biopsy can be performed. Here, we describe three cases including a unique and rare case of metastatic SPN. Clinicians should be aware of this relatively rare pancreatic lesion as its presentation may be insidious and early imaging is key. Once diagnosed, physicians should pursue multidisciplinary discussions with early surgical management even in metastatic disease, as outcomes are excellent with a favorable prognosis.Figure 1.: MR Imaging - SPN.Figure 2.: Endoscopic US - SPN.Figure 3.: Histopathology - SPN.