Unusual pulmonary nodules diffusion from epithelial‑myoepithelial carcinoma on 18F‑FDG PET/CT: A case report.

Epithelial-myoepithelial carcinoma (EMC) is a rare low-grade malignant tumor with uncommon regional lymph node metastasis and distant metastasis. The diagnosis of this disease primarily relies on the examination of pathological morphology and immunohistochemical staining, as its clinical symptoms and imaging findings are non-specific. This makes it more difficult to provide specific information about EMC lung metastasis. The present report describes a biopsy-confirmed case of pulmonary metastases arising from EMC of the parotid. The pulmonary nodules were dispersed throughout both lungs and exhibited varying degrees of fluorodeoxyglucose (FDG) uptake on positron emission tomography-computed tomography scans. Additionally, the pathological and immunohistological presentation of the lung mass was similar to that of the primary lesion. Several pulmonary nodules exhibiting varying degrees of FDG uptake may be considered a distinctive sign of metastasis on EMC imaging. Reviewing the present case, along with other similar rare cases in the literature, is crucial to accurately evaluate the imaging examinations of such patients to identify and establish an appropriate treatment plan for potential metastatic lung cancer. It also highlights the importance of not underestimating the malignant potential of EMC and the necessity for close follow-up.