Formation of a rare curve-shaped thoracolith documented on serial chest computed tomography images: A case report

BACKGROUND: Thoracolithiasis is a rare benign condition that manifests with one or more small nodules in the pleural cavity. In most cases, it is asymptomatic and found incidentally on chest imaging or during thoracic surgery. The thoracolithiasis formation process is rarely documented. Herein, we present a case of a rare, large, curve-shaped thoracolith, the formation of which was documented on serial computed tomography (CT) images. CASE SUMMARY: A 46-year-old male patient who denied any prior systemic disease was evaluated due to intermittent right-sided lateral chest pain lasting for a year. Chest radiography and CT revealed a circumscribed calcified nodule measuring 3.5 mm in the right lower lung lobe. Nodule biopsy revealed fungal infection, which was treated with antifungal medication. After 2 years of follow-up, the patient developed intermittent chest discomfort caused by pleural adhesions, and underwent video-assisted thoracic surgery with pneumolysis. Postoperatively, he developed empyema, which fully resolved with antibiotic therapy. Thereafter, he was followed up at the outpatient clinic and underwent chest CT twice per year. Over time, we observed thickening of the right distal pleura near the lower posterior mediastinum, and several sporadic calcified nodules with gradually increasing intensity, which eventually merged into a single calcified curve-shaped thoracolith measuring approximately 9 cm in length during the 5-year follow-up. CONCLUSION: This study documented the formation of a rare thoracolith shape observed for the first time.