This 44 year-old female with known pulmonary tuberculosis presented for a follow-up CT. A large mass with central hypodensity (click image for arrows) was shown in the anterior mediastinum, compressing the pulmonary trunk (MPA). It was not clear whether this lay within the pericardium, or anterior to it. This is thought to most likely represent a mediastinal tuberculous abscess or loculated tuberculous pericarditis. The patient was scheduled for a sternotomy to explore and drain the abscess, but did not attend.
Mediastinal tuberculous abscess may arise from caseous necrosis of mediastinal lymph nodes, or direct extension from the lung. Tuberculous pericarditis may arise from direct extension from the mediastinum or lung, or by haematogenous seeding. It complicates up to 1% of cases of tuberculosis. Tuberculous pericarditis is often calcific, and 10% of cases progress to constrictive pericarditis. Often only thickening of the pericardium is present.
References:
1. Harisinghani MG et al. Tuberculosis from Head to Toe. Radiographics. 2000;20:449-470
2. Kim HY, et al. Thoracic Sequelae and Complications of Tuberculosis. RadioGraphics 2001; 21:839–860
Credit: Dr Laughlin Dawes
