Extranodal Follicular Dendritic Cell Sarcoma Originating in the Pancreas: A Case Report

Follicular dendritic cell (FDC) sarcoma is a type of malignant tumor that originates from immune system-related FDCs. Pancreatic FDC sarcoma is a rare disease, and the specificity of the clinical presentation and laboratory results is unknown. We report the clinical process and imaging features of one case of pancreatic FDC sarcoma. A 67-year-old woman presented with a hypoechoic mass between the spleen and left kidney during a medical examination. The patient was hospitalized for further diagnosis. Her laboratory results did not present any obvious abnormal changes. Unenhanced and contrast-enhanced pancreatic computed tomography scans indicated a round mass with heterogeneous attenuation in the pancreatic tail, and a 3.5 × 3.6-cm solid mass with a cystic component was noted. Clear-cut, slight contrast enhancement was present in the solid part, whereas contrast enhancement was not observed in the cystic part. In addition, no obvious dilation was observed in the pancreatic duct, and no swollen lymph nodes were noted in the posterior peritoneum. Routine and contrast-enhanced pancreatic magnetic resonance imaging scans showed an abnormal signal indicative of a mass in the pancreatic tail, with a diameter of ∼35 mm and a clear boundary. A T2-weighted imaging scan showed a slight hyperintensity coupled with part of a hyperintensity, whereas T1-weighted imaging showed a slight hypointensity coupled with part of a hypointensity, and diffusion-weighted imaging showed a heterogeneous hyperintensity. The solid part of the lesion showed poor contrast enhancement through contrast-enhanced scanning, but contrast enhancement was not observed in the cystic part. Surgical tumor resection was performed, and the pathological diagnosis was pancreatic FDC sarcoma. The tumor did not recur based on short-term CT reexamination. Pancreatic FDC sarcoma is a rare disease, and the established clinical examinations and laboratory tests lack specificity. Imaging reveals a solid mass with a cystic component and a clear boundary. In addition, the solid part exhibits poor contrast enhancement. Although pancreatic occurrence is rare, a clinical pancreatic solid tumor with a cystic component should be identified by differential diagnosis.