Introduction: Tracheobronchopathia osteochondroplastica (TO) is a rare idiopathic benign disease of the large airways with a clinical prevalence of 0.2% to 0.7%. It is characterized by osteocartilaginous nodules that arise from the anterolateral aspects of the airway walls and project into the lumen of the trachea and bronchi. While typically asymptomatic, patients may experience dyspnea, excessive mucus production, or hemoptysis. The gold standard for diagnosis is a computed tomography (CT) scan and bronchoscopy, which often discover TO secondary to another condition. While no specific treatments exist for TO, the prognosis is generally favorable. This case report discusses a presentation of a male whose potential TO was incidentally discovered while evaluating his pleural effusion.

Case Presentation: A 70-year-old nonsmoker male with diabetes mellitus, end-stage renal disease on hemodialysis, and atrial fibrillation (not on anticoagulation) presented for continued evaluation of his unexplained bilateral pleural effusion.

The patient underwent a thoracentesis that confirmed an exudative pleural effusion (protein = 3.5 g/dl and LDH > 2/3 upper limit of normal). A follow-up CT scan of the chest revealed that the pleural effusion was more prominent on the left side, bibasilar atelectasis, compressive and rounded left lower lobe (LLL) atelectasis, scattered calcified granulomas, and left-sided pulmonary infiltrates.

To further evaluate, a bronchoscopy with bronchoalveolar lavage (BAL) and transbronchial biopsy was conducted the following month. Although the BAL and transbronchial biopsy results were negative, the bronchoscopy revealed yellowish tracheal nodules and bronchial nodules in the right mainstem and left upper lobe bronchi, suggesting potential Tracheobronchopathia Osteochondroplastica.

Discussion: TO is often a difficult condition to diagnose due to its benign nature and unknown etiology. This patient’s bronchoscopy revealing yellowish nodules along his tracheal and bronchial walls, CT showing potential calcifications, and biopsy indicating no malignancies collectively suggest a possible presentation of TO. There are no established follow-up guidelines, and it may be useful to see if the nodules increase in size or number over time and how this progression could affect the patient's symptoms and long-term outcomes. More work is needed to see if TOs are associated with or increase the risk for lung pathologies, such as pleural effusions, among other systemic diseases.

Conclusion: As TOs have very few effects, a diagnosis of TO is often made incidentally when evaluating other primary conditions. This patient’s presentation suggestive of tracheobronchopathia osteochondroplastica contributes to the limited literature on how TO may present.

References: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5474380/ https://www.mayoclinicproceedings.org/article/S0025-6196(19)30101-6/fulltext