Aggressive pediatric solid pseudopapillary neoplasms of the pancreas presented as acute abdomen: A case report and review of literature

Figure 1 Contrast-enhanced abdominal computed tomography/magnetic resonance imaging. A-F: Multiple metastatic lesions are demonstrated in hepatic segments VIII, VII, VI, V, IV (arrows); F: The portal venous phase of contrast-enhanced computed tomography shows compression and narrowing of the splenic vein; G: Fat-suppressed magnetic resonance imaging (MRI) images reveal intratumoral hemorrhage; H: T1-weighted contrast-enhanced MRI demonstrates heterogeneous enhancement within the tumor; I: T2-weighted MRI shows mixed cystic-solid signals. All images are displayed at an identical scale (scale bar in A: 1 cm per division, total 16 cm).

Figure 2 Histopathology and immunohistochemical examination of the tumor tissue removed after the surgery. A: Hematoxylin-eosin (HE) staining (× 40), pseudopapillary structures with fibrovascular cores, lined by poorly cohesive tumor cells; B: HE staining (× 40), tumor with hemorrhage, necrosis, and cholesterol clefts; C: HE staining (× 40), tumor cells infiltrating pancreatic parenchyma; D: Immunohistochemistry (IHC) (× 100), tumor cells showing nuclear progesterone receptor positivity; E: IHC (× 200), tumor cells demonstrating nuclear and cytoplasmic β-catenin positivity; F: IHC (× 200), tumor cells with cytoplasmic Vimentin expression. Scale bars: 200 μm in A-C; 100 μm in D; 50 μm in E and F.

Figure 3 Intraoperative imaging and postoperative gross specimens. A: Upon opening the greater omentum, the relative positions of the pancreas (denoted by a small oval) and the tumor (denoted by a blue arrow) are clearly visible; B: The distal pancreas and tail are transected using a stapler (denoted by a small oval); C: The surgical field following a distal pancreatectomy combined with splenectomy is depicted, highlighting the pancreatic stump (denoted by a small oval), the common hepatic artery (denoted by a yellow arrow), the left gastric vein (denoted by a blue arrow), the splenic vein stump (denoted by a white arrow), and the left kidney (denoted by a black arrow); D: The postoperative gross specimen reveals the tumor (denoted by a blue arrow) and the spleen (denoted by a white arrow).

Figure 4 Contrast-enhanced abdominal magnetic resonance imaging. A-E: A 17-month follow-up demonstrated that the multiple metastatic lesions in liver segments VIII, VII, VI, V, and IV remained stable (scale consistent with Figure 1) (arrows).