The figure shows predominantly pulmonary macrophages, which is a normal finding in BAL specimens. Pulmonary macrophages have low nuclear/cytoplasmic ratios, nuclei with fine chromatin, and abundant vacuolated cytoplasm. Most carcinomas will form at least some clusters, have cells with high nuclear-to-cytoplasmic ratios, and contain nuclei with irregular contours and coarse chromatin.
Mesothelioma usually presents in a pleural effusion (and not in a BAL specimen) as cell clusters and single cells. In contrast, macrophages tend to occur singly. Also, the presence of an asbestos body signifies asbestos exposure, but it is not a sine qua non of mesothelioma.
A patient with pulmonary hemorrhage will have hemosiderin-laden macrophages, characterized by golden-brown, intracytoplasmic particles of varying sizes. No hemosiderin is seen in the macrophages in this figure.
The presence of food particles and inflammation in a BAL specimen is highly suggestive of aspiration.
The figure demonstrates an elongated, dumbbell-shaped structure with a clear core coated by iron; this is consistent with an asbestos body. Patients with asbestos exposure may have asbestos bodies in the lung parenchyma and pleural plaques (thickening), as described in this patient. An asbestos body is a form of a ferruginous body. Non-asbestos ferruginous bodies have black or brown cores, in contrast to the clear cores seen in asbestos bodies.
