Diffuse Hypermetabolic Soft Tissue Nodules on FDG PET in Follicular Lymphoma

A 53-year-old man with follicular lymphoma on surveillance presented with new areas of rapidly growing adenopathy and soft tissue nodules 2 years after initial diagnosis. FDG PET imaging revealed innumerable subcutaneous and intramuscular nodules involving the scalp, neck, chest, abdomen, pelvis, and both upper and lower extremities, in addition to lymphadenopathy. After therapy, all soft tissue nodules resolved, and only a small volume of residual inguinal adenopathy remained, which had improved from baseline. Follicular lymphoma is an indolent B-cell lymphoproliferative disorder commonly presenting with enlarged axillary, cervical, femoral, and inguinal lymph nodes, whereas musculoskeletal and subcutaneous involvement is extremely rare.