Four rare extranodal sites seen on FDG PET/CT in a single patient of disseminated lymphoma
A 25-year-old gentleman, on anti-retroviral treatment for immunopositivity for HIV, since two years, presented to our institution 4 months back, with history of unexplained fever, weight loss and bilateral axillary swellings. On examination he had palpable bilateral axillary nodes. Recent CD4 count was 550 cells/mm3. A biopsy from the left axillary node confirmed it to be Non-Hodgkin's lymphoma (NHL) B cell type. Patient was then referred for a baseline whole body 18-F Fluorodeoxyglucose Positron Emission Tomography/Computed Tomography (FDG PET/CT) study. Maximum intensity projection (MIP) images [] revealed multiple foci of increased tracer uptake in bilateral cervical, axillary, mediastinal and retroperitoneal regions. In addition, there were foci of intense uptake on the left side of abdomen (arrow) and in the pelvis (arrow head), which appeared to be due to physiological tracer excretion into the urinary bladder. Axial fused PET/CT images revealed multiple enlarged FDG avid bilateral axillary and mediastinal nodes. In addition, FDG uptake was seen in enlarged bilateral adrenal glands, left being more than right [, arrows]. There was focal FDG uptake seen in the body of pancreas on axial-fused PET/CT images [, arrow]. FDG uptake in the retroperitoneal region corresponded on CT and fused PET/CT images to exiting nerve roots from lumbar vertebrae [Figure and , arrow]. Also, the FDG uptake in the pelvis which appeared to be excreted tracer in bladder, was in fact seen in the enlarged prostate gland on CT and fused PET/CT images [Figure and , arrow]. Patient received two cycles of intravenous bolus chemotherapy regimen, R-EPOCH (Rituximab with etoposide, vincristine, doxorubicin, cyclophosphamide, and prednisone) with methotrexate, after which he was referred for a FDG PET/CT study for treatment response assessment. Post-treatment FDG PET/CT study revealed no abnormal focus of FDG uptake in the entire body, suggestive of complete metabolic and morphological response to treatment [, MIP image].