Radiological “Triangle sign” in chest imaging in left lower lobe tuberculosis: A real puzzle

Abstract

Pulmonary tuberculosis is the most common etiology for lobar or multilobar atelectasis of the lung followed by foreign body and lung malignancy in the list. The left lower lobe atelectasis is underdiagnosed due to presentation as retrocardiac opacity, which is commonly missed by treating physicians. In this case report, a 46-year-old female presented with constitutional symptoms and retrocardiac triangular opacity in the chest cardiograph. High-resolution computed tomography thorax documented collapse with consolidation and necrosis in the posterior basal segment with loss of lung volume. Bronchoscopy documented purulent secretions coming out from the left lower lobe posterior basal segment without endobronchial abnormality. Bronchoscopy-guided bronchoalveolar lavage showed acid-fast bacilli, and nucleic acid amplification tests documented Mycobacterium tuberculosis genome without rifampicin resistance. She is treated with antituberculosis treatment for 6 months and observed good clinical, bacteriological, and radiological outcomes as “cure.” We recommend basic regular training of family physicians for common radiological signs for early diagnosis and timely treatment with a successful outcome.

Keywords

• high-resolution computed tomography thorax
• left lower lobe collapse
• pulmonary tuberculosis
• triangle sign