Visscher, Daniel W.

Abstract The term “bronchiolitis” refers to a broad morphologic spectrum of inflammatory events that are centered on small conducting airways. Bronchiolitis may be an isolated pathologic finding, although it is often a secondary consequence of diseases affecting other parts of the conducting apparatus or pulmonary acinus. Divergent causes of bronchiolitis may have similar microscopic findings. Hence, a pathologic diagnosis is nonspecific and not clinically meaningful unless placed in the context of relevant clinical and radiographic findings. Etiologically, most cases of bronchiolitis are infectious in nature or related to smoking. Increasingly, other causes of bronchiolitis have been recognized, including collagen vascular disease, idiopathic inflammatory bowel disease, or toxins/drugs. Many cases are idiopathic. Histologically, most examples of bronchiolitis demonstrate acute inflammation, usually corresponding to viral infection. Other well-defined histologic categories of bronchiolitis include bronchiolitis obliterans, in which there is fibroblast proliferation within airspaces, and follicular bronchiolitis, corresponding to lymphoid hyperplasia with formation of germinal centers. In recent years, several new forms of bronchiolitis have been recognized, including constrictive bronchiolitis, diffuse panbronchiolitis, and airway-centered fibrosis. This article highlights the clinical and pathologic features of these more recently described entities.

Purpose Polymorphisms in tamoxifen metabolizing genes affect the plasma concentration of tamoxifen metabolites, but their effect on clinical outcome is unknown. Methods We determined cytochrome P450 (CYP)2D6 (*4 and *6) and CYP3A5 (*3) genotype from paraffin-embedded tumor samples and buccal cells (living patients) in tamoxifen-treated women enrolled onto a North Central Cancer Treatment Group adjuvant breast cancer trial. The relationship between genotype and disease outcome was determined using the log-rank test and Cox proportional hazards modeling. Results Paraffin blocks were obtained from 223 of 256 eligible patients, and buccal cells were obtained from 17 living women. CYP2D6 (*4 and *6) and CYP3A5 (*3) genotypes were determined from 190, 194, and 205 patient samples and in 17 living women. The concordance rate between buccal and tumor genotype was 100%. Women with the CYP2D6 *4/*4 genotype had worse relapse-free time (RF-time; P = .023) and disease-free survival (DFS; P = .012), but not overall survival (P = .169) and did not experience moderate to severe hot flashes relative to women heterozygous or homozygous for the wild-type allele. In the multivariate analysis, women with the CYP2D6 *4/*4 genotype still tended to have worse RFS (hazard ratio [HR], 1.85; P = .176) and DFS (HR, 1.86; P = .089). The CYP3A5*3 variant was not associated with any of these clinical outcomes. Conclusion In tamoxifen-treated patients, women with the CYP2D6 *4/*4 genotype tend to have a higher risk of disease relapse and a lower incidence of hot flashes, which is consistent with our previous observation that CYP2D6 is responsible for the metabolic activation of tamoxifen to endoxifen.