Occurrence of Multiple Tumors in a Patient

An 81-year-old man initially presented with a right forearm mass that was found to be myxofibrosarcoma. In addition, he was found to have gastric and intragastric masses identified as neuroendocrine tumor (NET) and gastrointestinal stromal tumor (GIST; presenting synchronously), respectively, as well as a new left upper quadrant mass identified as desmoid tumor in the colon. The patient complained of melena, which was found to be due to metastatic myxofibrosarcoma in the transverse colon. Several reports have associated GIST with NET and some reports have associated GIST with sarcomas and NET with sarcomas; however, this is the first report to document all these tumors in a single patient. Several factors may have contributed to the development of these tumors, including growth factors secreted by NET, KIT mutation of GIST predisposing to additional tumors, immunosuppressed state, or an underlying genetic syndrome. This case highlights the importance of investigating for additional malignancies when a primary malignancy is discovered.