Solid pseudopapillary neoplasm (SPN) of the pancreas presenting with ascites misdiagnosed as pancreatic tuberculosis: a case report and literature review.

Background: Solid pseudopapillary neoplasm (SPN) is a rare pancreatic tumor that mainly affects young women. It is a low-grade malignant neoplasm, with an excellent prognosis after surgical treatment. We report herein a case of SPN presenting with ascites that was misdiagnosed as pancreatic tuberculosis (TB).

Methods: A 16-year-old female initially presented with a large volume of ascites. Contrast-enhanced ultrasound and computed tomography found a heterogeneous lesion in the pancreatic body, which had slight contrast enhancement on the arterial phase. Analysis of ascites showed it was exudative. Endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of the mass only revealed a few blood clots. The diagnosis was highly suggestive of a pancreatic TB. However, after 6 months of anti-TB therapy, the pancreatic lesion remained essentially unchanged. Subsequently, magnetic resonance imaging indicated a mixed solid and cystic lesion with a well-defined margin in the pancreatic body. Further EUS-FNA showed monomorphic neoplastic cells with papillary architecture and immunohistochemical analysis revealed that the tumor cells were positive for β-catenin, CD10, vimentin, cytokeratin, and synaptophysin. These findings were consistent with SPN. After distal pancreatectomy with splenectomy, postoperative pathology and immunohistochemical staining confirmed the diagnosis of SPN.

Conclusions: Clinicians should consider the possibility of SPN for pancreatic heterogeneous masses. Multiple diagnostic imaging modalities and EUS-FNA may contribute to the preoperative diagnosis of this disease.