Increased Tc-99m MDP Activities in Multifocal Atypical Ossifying Fibromyxoid Tumor

This case demonstrates extraosseous technetium-99m methylene diphosphonate (Tc-99m MDP) accumulation from an atypical ossifying fibromyxoid tumor (OFMT). A 63-year-old man presented with a 10-year history of a gradually enlarging, painless back mass. Physical examination revealed multiple hard, nontender subcutaneous nodules without signs of inflammation or pigmentation. Computed tomography scan of the back showed calcified masses. Whole-body bone scintigraphy revealed areas of increased Tc-99m MDP uptake in subcutaneous regions, suggesting extraosseous uptake. Histopathological examination of the back mass confirmed the diagnosis of atypical OFMT.