Appearance
Simple CWP is marked by the presence of 1–2mm nodular aggregations of anthracotic macrophages, supported by a fine collagen network, within the lungs. Those 1–2mm in diameter are known as coal macules, with larger aggregations known as coal nodules. These structures occur most frequently around the initial site of coal dust accumulation — the upper regions of the lungs around respiratory bronchioles. The coal macule is the basic pathological feature of CWP, and has a surrounding area of enlargement of the airspace, known as focal emphysema.
Continued exposure to coal dust following the development of simple CWP may progress to complicated CWP with progressive massive fibrosis (PMF), wherein large masses of dense fibrosis develop, usually in the upper lung zones, measuring greater than 1 cm in diameter, with accompanying decreased lung function. These cases generally require a number of years to develop. Grossly, the lung itself appears blackened. Pathologically, these consist of fibrosis with haphazardly-arranged collagen and many pigment-laden macrophages and abundant free pigment. Radiographically, CWP can appear strikingly similar to silicosis. In simple CWP, small rounded nodules (see ILO Classification) predominate, tending to first appear in the upper lung zones. The nodules may coalesce and form large opacities (>1 cm), characterizing complicated CWP, or PMF.
Read more about this topic: Coalworker's Pneumoconiosis
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