Endoscopic ultrasound-guided fine needle aspiration of solid pseudopapillary tumors of the pancreas: a report of three cases
A 33-year-old male visited our hospital for evaluation of an adrenal mass, which was suspected in abdominal ultrasonography during a general examination. An abdominal CT scan revealed a mass in the tail of the pancreas, not the adrenal gland. The physical examination was unremarkable. Laboratory studies revealed slightly increased AST and ALT: WBC, 6.49 × 103/µL; hemoglobin, 14.3 g/dL; platelets, 269 × 103/µL; AST/ALT, 66/101 U/L; amylase/lipase, 78.9/45 U/L; CA 19-9, 28.7 U/mL. The CT scan showed a 4-cm heterogeneous low-attenuation mass with a smooth margin in the tail of the pancreas. The lesion demonstrated iso-enhancement relative to the surrounding pancreas in the adrenal enhancement phase. MRI demonstrated a 4.2-cm, well-demarcated cystic mass involving the tail of the pancreas. In the MR arterial phase, the lesion showed a relatively low enhancement pattern. EUS showed that the 5-cm cystic mass consisted of numerous tiny cysts ().\nEUS-FNA and TCB were performed. We used a 25-gauge needle for FNA and a 19-gauge needle for TCB and approached the pancreas using a transgastric pathway. Both cell aspirates and tissue sections were obtained.\nSmear and cell block sections showed hypercellularity and sheets and clusters of monotonous small cells with round nuclei. The tissue sections did not display typical pseudopapillary features. We performed immunohistochemical staining to identify other cystic lesions in the pancreas. Immunostaining was positive for β-catenin and CD10, whereas staining was negative for neuroendocrine markers, such as synaptophysin and chromogranin. These immunohistochemical features implied that the mass would be a SPT. A laparoscopic spleen-preserving distal pancreatectomy was performed. The resected specimen showed a round solid mass, measuring 5 cm, with some cystic change due to necrosis. Microscopically, the tumor was composed of round tumor cells with numerous pseudopapillae and multifocal necrosis. The immunoprofile was consistent with the biopsy specimen. The final histopathologic diagnosis was SPT of the pancreas.