Racial Differences in Sarcoidosis Granuloma Density

Study Objectives While sarcoidosis generally inflicts a greater morbidity on African-American compared with Caucasian patients, no studies have examined whether racial differences exist in the intensity of the histologic hallmark of sarcoidosis, noncaseating granulomas. Design and Setting The study was conducted as a retrospective case series in a tertiary referral center. Patients The study included 187 patients with histopathologic confirmation of sarcoidosis by trans- and/or endobronchial biopsy between July 1991 and December 2001. Measurements and Results Granuloma density was the average number of granulomas per biopsy piece on the slide with the most intense granulomatous inflammation at fourfold magnification. Overall, African-American patients had a twofold greater median granuloma density than Caucasians (p = 0.005). In a negative binomial multivariate model, radiographic pattern had the strongest association with granuloma density, with Scadding stage II and III patients having adjusted granuloma densities of 60% (p = 0.005) and 105% (p = 0.0001) higher than stage I patients. In the specific-tissue types, radiographic stage–adjusted granuloma densities in African-American patients were 49% greater in bronchial tissue (p = 0.03), but only a 27% greater in alveolar tissue (p = 0.51). Conclusions A greater granuloma density in bronchiolar lung tissue of African-American sarcoidosis patients may explain racial differences in diagnostic yield by lung biopsy and disease severity at diagnosis. This association persists even after controlling for Scadding radiographic stage, a measure of disease severity strongly associated with granuloma density.