From the Guidelines
Evaluation of apical lung pleural thickening requires a comprehensive approach, and I strongly recommend starting with a high-resolution chest CT scan with contrast to better characterize the thickening, as suggested by the most recent study 1. This approach is crucial in identifying the underlying cause of the pleural thickening, which can be due to various factors such as prior tuberculosis infection, malignancy, asbestos exposure, chronic fungal infections, radiation therapy effects, or extrapleural fat deposition. The use of high-resolution chest CT scan with contrast is supported by the study 1, which highlights the importance of cross-sectional imaging in the diagnostic workup of benign pleural effusions in adults.
Key considerations in the evaluation of apical lung pleural thickening include:
- Clinical correlation with patient history, including assessment of risk factors such as smoking history, occupational exposures, prior lung infections, and any systemic symptoms like weight loss, fever, or hemoptysis
- Pulmonary function tests to assess any functional impairment
- PET-CT scan to evaluate for metabolic activity suggestive of malignancy, if the CT findings are concerning
- Tissue sampling through CT-guided needle biopsy or video-assisted thoracoscopic surgery (VATS) biopsy for definitive diagnosis, if necessary
It is essential to note that the study 1 provides the most recent and highest quality evidence, and its findings should be prioritized in the evaluation and management of apical lung pleural thickening. The study's definition of diffuse pleural thickening (DPT) as shouldered pleural thickening measuring >5 cm axially by >8 cm craniocaudally with a minimum thickness of 3 mm is particularly relevant in this context. Overall, a comprehensive approach that incorporates the latest evidence and guidelines is necessary to ensure optimal outcomes in patients with apical lung pleural thickening.
From the Research
Evaluation of Apical Lung Pleural Thickening
- Apical lung pleural thickening can be associated with various conditions, including pulmonary tuberculosis 2 and malignant pleural mesothelioma 3.
- High-resolution computed tomography (HRCT) scans have been used to evaluate apical lung pleural thickening, showing that extrapleural fat with interspersed vessels can account for most of the plain radiographic opacity 2.
- A study of 28,727 chest X-rays found that pleural thickening was the most common abnormal radiological finding, with 92.2% of cases involving the apex of the lung, particularly on the right side 4.
- The prevalence of pleural thickening increases with age, and is more common in males than females, and in current smokers or ex-smokers than in never smokers 4.
- CT findings of pleural tuberculosis (PTB) can be similar to those of malignant pleural dissemination (MPD), but nodular pleural thickening is more frequently observed with MPD than PTB 5.
- Intraparenchymal malignant pleural mesothelioma can mimic lung cancer, and should be considered when lung nodules are present, to prevent misdiagnosis and delayed treatment 3.
Radiological Features
- HRCT scans can show extrapleural fat, thickened pleura, and atelectatic lung in patients with apical lung pleural thickening 2.
- Chest X-rays can show a homogeneous apical opacity, which can be associated with pleural thickening 4.
- CT findings of PTB can include circumferential pleural thickening, mediastinal pleural involvement, nodular thickening, and pleural thickening >1 cm 5.
- CT features of MPD can include nodular pleural thickening, mediastinal pleural involvement, circumferential thickening, and pleural thickening >1 cm 5.
Clinical Associations
- Pleural thickening is more common in males than females, and in current smokers or ex-smokers than in never smokers 4.
- The prevalence of pleural thickening increases with age, ranging from 1.8% in teenagers to 9.8% in adults aged 60 years and older 4.
- A tall, thin body shape may predispose to pleural thickening, suggesting that disproportionate perfusion, ventilation, or mechanical forces in the lungs may play a role in its development 4.