Two Simultaneous Primary Cancers: A Case Report.

When a patient is diagnosed with more than one tumor in the same organ or in a different one, there may be multiple primary tumors. We present the case of a patient with an initial diagnosis of undifferentiated pleomorphic sarcoma (UPS) of the posterior region of the neck in whom an extension study was requested after surgery prior to the systemic therapy; tumor activity was identified in the left testicle, and radical orchiectomy was performed with the result of non-Hodgkin lymphoma (NHL) B cells. Multiple primary neoplasms have different histologies and different sites of origin. The interest of the case arises from the clinical presentation in which the patient is being staged due to a previously diagnosed malignant tumor, and a second tumor is detected in the positron emission tomography (PET) scan. Because of the characteristics of the first neoplasm, it is very unlikely that it could correspond to metastasis of the known primary tumor; therefore, it is suspected to be another primary tumor that requires histological confirmation.