Tc-99m MDP uptake in retroperitoneal malignant peripheral nerve sheath tumor and its metastases.

Extraosseous uptake of Tc-99m MDP has been reported in various pathologic conditions. Because of the opportunity of make an additional diagnosis, extraskeletal distribution of tracer should be inspected in every case. Malignant peripheral nerve sheath tumor (MPNST) is a rare type of neurogenic tumor. Its main clinical manifestation is a mass with or without pain. MPNST can be seen in all 4 extremities, the trunk, head and neck regions, but most commonly occur in the thigh, buttocks, and supraclavicular regions. Presented here is a rare case of MPNST in which Tc-99m MDP uptake by the primary lesion and metastases were clearly demonstrated on bone scintigraphy.