New insights into solitary bronchial mucosal neuroma: A case report and literature review.

Solitary bronchial mucosal neuroma is an exceptionally rare benign neurogenic tumor, with only four cases reported to date. Its etiology remains unclear, and histologically it resembles a traumatic neuroma despite arising in the absence of prior injury or surgery. Here, we present the fourth reported case of solitary bronchial mucosal neuroma and review all documented cases to better characterize its clinicopathological features and pathogenesis. Case Presentation. A 58-year-old man with a history of pulmonary tuberculosis presented with cough, purulent sputum, and hemoptysis. Imaging and bronchoscopy revealed a yellowish-white endobronchial lesion causing luminal stenosis. Histological examination of biopsy specimens demonstrated disorganized nerve bundles beneath the mucosa, comprising S-100-positive Schwann cells and neurofilament-positive axons, with variable epithelial membrane antigen-positive perineurial cells. Screening for multiple endocrine neoplasia type 2B (MEN2B) and other syndromic associations was negative. Wedge resection additionally revealed an incidental 2 mm carcinoid tumorlet. Conclusion. Solitary bronchial mucosal neuroma predominantly affects middle-aged to elderly individuals, often in the context of chronic inflammatory lung disease. It likely represents a traumatic neuroma of autonomic origin, with chronic inflammation playing a contributory role. Solitary bronchial mucosal neuroma should be considered in the differential diagnosis of endobronchial lesions and may coexist with carcinoid tumors. The lesion follows a benign course and is curable with complete resection. Further studies are needed to elucidate its pathogenesis and clinical spectrum.