Pretherapeutic 18F-PSMA PET/CT Reveals Incidental Tracheal Epithelial–Myoepithelial Carcinoma

A 75-year-old man with newly diagnosed high-risk prostate cancer (cT3bN0M0) underwent ¹⁸F-PSMA PET/CT, which demonstrated intense tracer uptake in a left tracheal mass causing near-complete luminal obstruction, raising suspicion of a primary lung malignancy or metastatic disease. Endoscopic debulking was performed due to progressive respiratory symptoms with dyspnea. Histopathology and immunohistochemistry (p63, SMA, CK5/6 positive; PSA, NKX3.1, and AR negative, with downregulated PSMA-expression) established the diagnosis of low-grade epithelial-myoepithelial carcinoma of the trachea. Following debulking, the patient's symptoms resolved, and a watchful-waiting strategy was adopted for the tracheal tumor, while curative-intent therapy for prostate cancer continued. This case highlights that ¹⁸F-PSMA PET/CT may reveal rare, intensely PSMA-avid non-prostatic neoplasms and underscores the importance of recognizing atypical uptake patterns to avoid misinterpretation during prostate cancer staging.