Integrated diagnostic evaluation of multiple malignant neoplasms via ^99m Tc‑MDP three‑phase bone imaging: A case report

Multiple primary malignant neoplasms (MPMNs) are two or more independent cancer types arising in different organs, either at the same time or one after another. Diagnosing MPMNs is often difficult as multiple organs can be involved and early symptoms may be subtle or absent. The present study reports the case of a 79-year-old man with a recurrent left forearm mass whose ^99mTc-labeled methylene diphosphonate (^99mTc-MDP) three-phase bone scan unexpectedly showed a classic 'superscan'. Surgical pathology confirmed two primary malignancies: Subcutaneous myxofibrosarcoma and prostate cancer with extensive bone metastases. The present case illustrates how ^99mTc-MDP imaging, especially when combined with single photon emission computed tomography/computed tomography, can reveal both soft-tissue tumors and diffuse skeletal involvement, thereby improving early detection of MPMNs.