Solid Pseudopapillary Tumor of the Pancreas: A Single-center Experience and Review of the Literature

Abstract

Background: Solid pseudopapillary tumors (SPTs) of the pancreas are a rare occurrence, not exceeding 1-2% of all exocrine pancreatic tumors. SPT was first described in 1959 as "papillary tumor of the pancreas, benign or malignant" and affects mainly young women, in their second or third decade of age. These tumors are of low malignant potential, unclear pathogenesis, grow gradually and become considerably large before causing symptoms. A typical clinical presentation is often described by affected patients and, in some cases, an SPT is an incidental finding during the time the patient undergoes medical imaging studies for other health issues. SPT is frequently located at the head or tail of the pancreas. Metastases are rare but, when present, affect predominantly the liver.

Patients and methods: We report a series of five SPT cases in female patients 13-47 years old, presenting with almost identical symptoms of upper abdominal discomfort and non-tender palpable mass. Two out of five patients also reported vomiting, nausea and poor appetite as co-existing non-diagnostic symptoms. Only one patient presented without any symptoms. Tumor location and dimensions varied. One patient underwent a pancreatoduodenectomy (Whipple's procedure), while the remaining patients underwent distal pancreatectomy with concomitant splenectomy.

Results: Perioperative morbidity and mortality was zero. All five patients are disease-free at a follow-up from 3 months to 13 years. Histopathology reports supported the diagnosis of SPT and no metastatic disease was present in any of the patients.

Conclusion: The overall prognosis of SPT of the pancreas is excellent due to its favorable biological features, even in the presence of distal metastasis. Although surgical resection is often curative, a close follow-up is advised in order to diagnose a possible local recurrence or distal metastasis and choose the proper therapeutic option for the patients.

Keywords: Solid; neoplasm; pancreas; pseudopapillary; review; tumor.

Figure 1. A 16-cm solid pseudopapillary tumor (SPT) located in the body/tail of pancreas. a, b: Non-gadolinium-enhanced abdominal magnetic resonance imaging (MRI) (coronal and sagittal images) revealed a heterogeneous well-defined 13.5×10×8 cm mass involving the pancreatic tail; c: Encapsulated cystic tumor with hemorrhagic, friable content located in the pancreatic tail; d: Gross appearance of the resected solid pseudopapillary tumor.

Figure 2. A 6-cm solid pseudopapillary tumor (SPT) located in the head of pancreas. a: Abdominal coaxial tomography (CT) reported a 3.5×4.8×4.2 cm heterogeneous mass connected to the pancreatic head with loci of tissue necrosis in both the center and the periphery of the mass; b, c: Encapsulated tumor with hemorrhagic cystic and yellowish solid areas; d: Specimen of resected pancreatic head with the tumor, duodenum and gallbladder; e: Neoplastic tissue showing solid and pseudopapillary growth pattern and poorly cohesive monomorphic cells (hematoxylin and eosin (H&E), ×50); f: Numerous intracellular hyaline globules (H&E, ×400)

Figure 3. An 8-cm solid pseudopapillary tumor (SPT) located in the body/tail of pancreas. a: The SPT was found to occupy the largest part of the posterior surface of the pancreas, arising from the neck and developed towards to the body and tail of the pancreas; b: Splenic vein (SV) went through the tumor, with the late reaching the join of splenic vein to superior mesenteric vein (SMV); c: Gross appearance of the SPT and spleen after complete resection; d: Neoplastic cells with clear cytoplasm and hyalinized fibrous bands (hematoxylin and eosin (H&E), ×100)

Figure 4. An 1.5-cm solid pseudopapillary tumor (SPT) located in the body of pancreas. a: Positron emission tomography (PET) study showing increased uptake of 18F-fluorodeoxyglucose (F-18 FDG) in the periphery of the pancreatic tumor (standardized uptake values (SUV)max=3.0); b: SPT involving the splenic artery; c: Circumscribed brown-yellow tumor with solid and friable areas; d: Gross appearance of the resected SPT and spleen after complete resection

Figure 5. An 8-cm solid pseudopapillary tumor (SPT) located in the body/tail of pancreas. a, b: Abdominal magnetic resonance imaging (MRI) (coronal and sagittal images) reported a 11.6-mm focal lesion situated anterior to the spleno-portal vein junction; c: Encapsulated tumor with microcystic cut surface in the body of the pancreas; d: Gross appearance of the resected SPT and spleen