Bronchoalveolar Lavage in Liquid Paraffin Pneumonitis: Discussion (1)

Bronchoalveolar Lavage in Liquid Paraffin Pneumonitis: Discussion (1)These seven cases of liquid paraffin pneumonitis show that the disease still occurs and that its diagnosis can be made by cytologic and biochemical analysis of BALF. The macroscopic aspect of the BALF with oily substances floating on its surface may first evoke the diagnosis. Microscopic examination of the cell pellet showed that almost all the AM had a typical abnormal foamy appearance due to empty vacuoles not stained with the usual dyes. Positive staining of AM with dyes specific for lipids, Sudan B, Sudan III, and oil red O showed that the material contained in the vacuoles was made of neutral lipids. Ultrastructural examination of these macrophages showed the presence of many clear vacuoles occupying a large part of the cytoplasm. The vacuoles were empty because liquid paraffin was extracted during fixation and staining. The vacuoles appeared to be within phagosomes because they were bound in place by a single membrane. buy ampicillin
These large amounts of vacuolated material within the AM are similar to the previous histologic findings of liquid paraffin pneumonia. These foamy macrophages with large cytoplasmic vacuoles are suggestive of liquid paraffin pneumonitis but must be distinguished from the vacuolated AM found in PAP, in cholesterol pneumonia, after exposure to silicone, or exposure to polyvinylpyrrolidone. In active PAP, there are a few alveolar macrophages, and their nuclei are often piknotic and the vacuoles are much smaller than in paraffin loaded AM. The abundant intracellular and extracellular material is strongly stained with PAS. In the case of cholesterol pneumonia, which usually occurs distal to an obstructing bronchial lesion, AM inclusions are deeply stained with dyes for lipids and give a positive PAS reaction.