Ferruginous bodies in cases with occupational and non-occupational exposure to inorganic dusts. A study with 40 matched cases.

In this study we evaluated the usefulness of ferruginous bodies (FB) quantification in lung digest and histologic sections from 40 patients with a history of exposure to inorganic dusts. The patients were matched with 40 cases without occupational exposure. The samples of peripheral lung tissue were digested and all FB were quantified. Lung sections were also evaluated in order to confirm the presence of FB. The concentrations of FB in the patients were higher than the controls (Wilcoxon test, p < 0.001). The patients group showed a median concentration of 194.5 FB/g of dry lung tissue (FB/g) vs. 34.0 FB/g in the controls. Seventy percent of the patients had more than 100 FB/g vs. 27.5% in the controls cases. Pneumoconiosis was diagnosed in 19 patients, 17 had FB/g above 100 and only 4 were positive to FB in lung sections. We can conclude that lung digest and FB counts help to confirm exposures to inorganic dusts above the background values found in the general population. FB counts can help when the clinical file does not confirm the exposure.