What is the most likely diagnosis in a coal‑mine mechanic with an abnormal chest X‑ray showing left‑sided pleural fibrosis confirmed on CT chest?

Asbestos-Related Pleural Disease (Most Likely Diagnosis)

The most likely diagnosis in a coal mine mechanic with left-sided pleural fibrosis on CT chest is asbestos-related pleural disease, specifically diffuse pleural thickening or pleural plaques from asbestos exposure. 1

Rationale for Asbestos Over Coal Worker's Pneumoconiosis

While coal miners are classically at risk for coal worker's pneumoconiosis (CWP), the isolated pleural fibrosis pattern strongly suggests asbestos exposure rather than coal dust. Here's the critical distinction:

Why Asbestos Fits Better:

• Pleural disease is the hallmark of asbestos exposure 1. Asbestos causes collagen deposition in the pleura resulting in subpleural thickening that may calcify, and this has become the most prominent feature of asbestos exposure in modern surveillance 1

• Coal worker's pneumoconiosis primarily affects lung parenchyma, not pleura. CWP characteristically presents with small rounded or irregular opacities in the lung parenchyma, predominantly in upper zones, with progression to progressive massive fibrosis (PMF) 2, 3, 4. Isolated pleural thickening is uncommon in CWP, occurring in only 18% of cases 2

• Mechanics in coal mines have significant asbestos exposure from brake linings, gaskets, insulation materials, and equipment maintenance—often more than the miners themselves who primarily encounter coal dust

Imaging Pattern Analysis:

The CT findings of isolated pleural fibrosis without mention of parenchymal nodules or upper lobe predominance makes this asbestos-related rather than coal-related 1.

Key distinguishing features:

• Asbestos: Bilateral pleural plaques, diffuse pleural thickening, may have lower lobe parenchymal fibrosis if asbestosis present 1
• CWP: Small nodules (rounded or irregular opacities), upper lobe predominance, can progress to PMF, minimal pleural involvement 2, 3

Clinical Approach

Confirm the Diagnosis:

1. Detailed occupational history: Specifically ask about:

   • Brake repair work
   • Gasket replacement
   • Work with insulation materials
   • Equipment maintenance involving friction materials
   • Duration and intensity of these exposures (latency typically >20 years) 1

2. Review CT characteristics 1:

   • Bilateral vs unilateral pleural thickening (bilateral more typical)
   • Presence of calcification (highly specific for asbestos)
   • Check for parenchymal changes suggesting asbestosis
   • Look for "holly leaf" pattern of calcified plaques

3. Assess for complications:

   • Restrictive lung function (FVC, TLC, DLCO) if parenchymal disease present 1
   • Screen for malignancy risk (mesothelioma, lung cancer) 5

Important Caveats:

• Unilateral pleural thickening is less typical for asbestos but can occur, especially following benign asbestos pleural effusion 1
• Always exclude malignancy in any coal/asbestos-exposed worker with pleural abnormalities—consider contrast-enhanced CT or PET/CT if there's diagnostic uncertainty about mesothelioma 5
• Mixed exposures are common: This patient could have both asbestos-related pleural disease AND early CWP, though the pleural findings dominate the presentation 1

Management Priorities:

• Surveillance for mesothelioma and lung cancer given the established increased malignancy risk with asbestos exposure 5
• Pulmonary function testing to assess restrictive impairment if symptomatic 1
• Smoking cessation if applicable (synergistic cancer risk)
• Document for compensation purposes using ILO classification if needed 1

The combination of occupational setting (coal mine mechanic, not miner), isolated pleural fibrosis pattern, and CT confirmation makes asbestos-related pleural disease the leading diagnosis over coal worker's pneumoconiosis.