Synchronous Pulmonary Malignancy Detected During PSMA Ligand PET/CT for Initial Staging of Prostate Cancer: a Case Report.

We present a case of an 83-year-old man with underlying colorectal cancer who underwent a gallium-68 prostate specific membrane antigen-11 positron emission tomography/computed tomography (⁶⁸ Ga-PSMA-11 PET/CT) for the initial staging of prostate cancer. PET / CT revealed two mildly PSMA-avid lung nodules without evidence of PSMA-avid nodal or bony metastasis. Subsequently, a wedge pulmonary resection was performed and the histopathology and immunohistochemistry of the nodules were consistent with synchronous primary lung cancer. Because differentiating synchronous primary lung cancer from pulmonary metastasis of prostate cancer can significantly affect treatment strategies and pulmonary metastasis rarely presents during initial staging of prostate cancer, synchronous primary lung cancer should be included in the differential diagnosis of pulmonary lesions in initial staging of ⁶⁸ Ga-PSMA-11 PET/CT regardless of PSMA avidity. The lack of nodal or bony metastases also decreases the likelihood of lung metastasis, and a tissue diagnosis may be required.