Challenges in Diagnosing Bronchial Mucous Gland Adenoma Specimens Resected with Endoscopic Snare: A Case Report

Bronchial mucous gland adenoma (BMGA) is a rare benign tumor originating from the bronchial glands. A 71-year-old man was found to have right upper lobe atelectasis. A bronchoscopy revealed a polypoid lesion obstructing the right upper lobe bronchus. An initial endoscopic biopsy was inconclusive, yielding a differential diagnosis of mucous gland adenoma or invasive mucinous adenocarcinoma. A snare resection was performed to obtain an adequate specimen for definitive diagnosis. Although the tumor, which originated from the right B3 bronchus, was resected, a residual portion remained. Due to the inability to exclude adenocarcinoma and the persistence of atelectasis, a robotic-assisted right upper lobectomy with bronchial wedge resection and bronchoplasty was performed. Postoperative pathological analysis showed no residual tumor, and a comprehensive review of the snare-resected specimen with immunohistochemistry, which was positive for NKX3.1, confirmed the final diagnosis of BMGA. We present this case of BMGA to highlight the diagnostic challenges associated with this rare tumor, which necessitated surgical intervention despite an endoscopic resection.