Synchronous Pancreatic Solid Pseudopapillary Neoplasm Masquerading as Extralymphatic Involvement on 18F-Fluoro-2-deoxy-D-glucose Positron Emission Tomography/Computed Tomography in a Case of Hodgkin's Lymphoma.

Solid pseudopapillary neoplasm (SPN) is a rare histopathologic variant of pancreatic tumors. Franz first described this tumor as a "papillary tumor of the pancreas, benign or malignant." In 1996, the World Health Organization named this tumor as SPN of the pancreas. It has a female preponderance with a male-to-female ratio of 1:9. A 30-year-old female who is a known case of lymphocyte-rich classic Hodgkin's lymphoma underwent 18F-fluoro-2-deoxy-D-glucose (FDG) positron-emission tomography/computed tomography (PET/CT) for initial staging which showed intense metabolic activity in bilateral enlarged cervical and splenic hilar lymph nodes. Furthermore, intense metabolic activity was noted in hypodense lesion in the tail of the pancreas, and she was reported to be having Stage IIIE disease. Post chemotherapy, 18F-FDG PET/CT showed disappearance of all previously metabolically active lymph nodes but persisting metabolically active lesion in tail of the pancreas. Hence, we reported as complete metabolic response of Hodgkin's lymphoma as per the Lugano criteria with suspected synchronous primary in the tail of the pancreas. Post distal pancreatectomy, histopathological examination and immunohistochemistry revealed the pancreatic lesion as SPN. SPN of the pancreas itself is a rare tumor and the presence of SPN in a patient with Hodgkin's lymphoma as synchronous primary is very rare. Due to the high density of mitochondria and the hypervascular nature of the tumor, there is an accumulation of 18F-FDG in SPN tumor cells. Patients with SPN usually have a very good prognosis after surgery. The five-year survival rate is as high as 95%-97%.