1038 Evaluation of the skin microbiota in a health Chinese population

Abstract

Introduction: Necrobiosis lipoidica (NL) is a chronic, granulomatous disease linked to diabetes mellitus (DM). Our aim was to characterize its histology and inflammatory cell features to better understand its etiology. Methods: A retrospective study was performed within Mayo Clinic from 1992 to 2017. Inclusion into the study required biopsy-proven NL where the histopathology and inflammatory infiltrate of 93 biopsies were reviewed by a dermatopathologist. Results: The granulomatous changes of NL were most commonly diffuse (84% No DM, 97% DM-2, 60% DM-1, p¼0.048). The pattern of inflammation was most often palisaded 54% and or tiered/layered 65% (59% No DM, 80% DM-2, 40% DM-1) involving the mid-dermis (98% No DM, 100% DM-2, 80% DM-1) (p¼0.016). Sarcoidal granulomas were more common in those without DM (24% No DM, 3% DM-2, 0% DM-1) (p¼0.025). The subcutis was involved in the non-DM and DM-2 30% of the time. Mucin was present more commonly in diabetics (17% non-DM, 53% DM-2, and 40% DM-1) (p¼0.01). Perivascular inflammation was present in 82% of cases and composed predominantly of lymphocytes (93% No DM, 100% DM-2, 80% DM-1) (DM-2 vs DM-1 p¼0.013) and plasma cells 73%. Lymphocytic infiltrates were ubiquitous and plasma cells (81% No DM, 83% DM-2, 40% DM-1) (DM-2 vs DM-1 p¼0.033) were significantly different in the infiltrate. Eosinophils were present (38% No DM, 10% DM-2, 20% DM-1) (p¼0.02) and were seen in differing amounts in the dermis (p¼0.049). Neutrophils were present (14% No DM, 50% DM-2, 60% DM-1) (p<0.001) and were seen in differing amounts in the dermis (12% No DM, 47% DM-2, 60% DM-1) (p <0.001). Giant cells were seen in 82% of cases. Foamy histiocytes were seen in 71% of cases and were often widespread (63% No DM, 30% DM-2, 33% DM-1) (p¼0.042). Conclusion: While sharing similar histopathology, the inflammatory profiles between the NL subgroups of Non-DM, DM-2 and DM-1 are distinct. NL may have different mechanisms between groups.