A rare case of endobronchial mucoepidermoid carcinoma of the lung presenting as non-resolving pneumonia.

Background: Mucoepidermoid carcinoma (MEC) is the most common malignant salivary gland tumor, and MECs of the lung are rare, accounting for 0.1-0.2% of malignant lung tumors. Pulmonary MECs are commonly found in the segmental or lobar bronchi, rarely presenting as endobronchial lesions.

Case presentation: Here we describe the case of a 21-year-old female with no comorbid conditions who presented at the emergency room with a cough, yellow phlegm, pleuritic chest pain, and a subjective fever. These symptoms had been present for approximately one week prior to the patient's arrival at the hospital. A chest X-ray revealed right lower lobe alveolar infiltrate and computed tomography of the chest showed dense consolidation of the right lower lobe with ovoid intraluminal density in the right main stem bronchus. Upon fiber optic bronchoscopy, an endobronchial lesion was found in the right main stem sparing the right upper lobe uptake. Endobronchial biopsy results was consistent with MEC of the lung. The patient underwent a bilobectomy with complete resection of the tumor.

Conclusion: Endobronchial MEC is a rare type of salivary gland tumor. Patients with low-grade MECs have a good prognosis, whereas those with high-grade MECs, which are aggressive and associated with metastatic disease, have a poor prognosis. However, early identification and surgical resection can result in a good prognosis.