Solid Pseudopapillary Neoplasm With Extensive Intratumoral Hemorrhage.

Solid pseudopapillary neoplasm (SPN) of the pancreas occurs predominantly in young women and commonly contains hemorrhagic and degenerative components that can complicate imaging assessment. We report the case of a 19-year-old woman who presented with abdominal distension and decreased appetite. Multiphasic abdominal CT, including an unenhanced phase, demonstrated a well-circumscribed cystic and solid mass in the pancreatic head, with internally hyperattenuating areas on the unenhanced images and mild heterogeneous enhancement of the non-cystic component. MRI demonstrated peripheral and internal intrinsic T1 hyperintensity, compatible with blood products, markedly heterogeneous T2 signal, and restricted diffusion in a non-cystic portion that also showed post-contrast enhancement, along with an enhancing capsule. The measured apparent diffusion coefficient (ADC) was approximately 0.98 × 10⁻³ mm²/s. Because clotted blood may also restrict diffusion, the diffusion-weighted imaging (DWI) and ADC findings were interpreted together with the conventional and post-contrast images rather than being used alone to identify viable tumor tissue. The patient underwent laparoscopic pancreaticoduodenectomy. Gross examination revealed a cystic and solid tumor containing abundant bloody fluid, and microscopy confirmed conspicuous hemorrhage. Immunohistochemistry showed nuclear and cytoplasmic β-catenin positivity, nuclear progesterone receptor positivity, and CD10 and vimentin positivity, supporting the diagnosis of SPN. Resection margins and sampled lymph nodes were negative. Correlative analysis of CT and MRI findings with pathological and immunophenotypic features may improve diagnostic confidence.