Granuloma faciale: a cutaneous lesion sharing features with IgG4-associated sclerosing diseases

The pathogenesis of granuloma faciale (GF), framed in the group of cutaneous vasculopathic dermatitis, is poorly understood. The present study investigated whether GF might be part of the spectrum of IgG4-related sclerosing diseases (IgG4-RD). Erythema elevatum diutinum (EED), believed to belong to the same group of disorders as GF, was also studied for comparison. Thirty-one biopsies of GF obtained from 25 patients (18 men, 7 women) and 5 cases of EED (4 women and 1 man) were analyzed morphologically and for the expression of IgG and IgG4 by immunohistochemistry. The distribution of Th1, T regulatory and Th2 T-cell subsets, respectively, identified by anti-T-bet, anti-FoxP3, and anti-GATA-3 antibodies, was also evaluated. The dermal inflammatory infiltrate in GF contained eosinophils and plasma cells in variable proportions. Obliterative venulitis was found in 16 cases, and storiform fibrosis, a typical feature of IgG4-RD, was observed in 8 cases and was prominent in 3 of them. On immunohistochemical analysis 7 of 31 biopsies (22.6%) from 6 GF patients fulfilled the criteria for IgG4-RD (IgG4/IgG ratio >40%, and absolute number of IgG4 per high-power field >50). Interestingly, the 6 patients were male, and 4 showed recurrent and/or multiple lesions. In an additional 5 cases, only the IgG4/IgG ratio was abnormal. None of the 5 EED cases fulfilled the criteria for IgG4-RD. The T-cell subsets in GF were quite variable in number, GATA-3 lymphocytes were generally more abundant, but no relationship with the number of IgG4 plasma cells was found. The study indicates that a significant number of GF cases are associated with an abnormal content of IgG4 plasma cells; this association was particularly obvious in male patients and in cases presenting with multiple or recurrent lesions. As morphologic changes typically found in IgG4-RD, such as obliterative vascular inflammation and storiform sclerosis, are found in GF, we suggest that GF might represent a localized form of IgG4-RD.