In Reply We read with interest the letter by Lehman et al about our 2 cases of IgG4-related disease (IgG4-RD) limited to the skin.1 In both cases, diagnosis of IgG4-RD was based on the presence of skin pseudolymphomatous nodules similar to those reported in previously published cases of cutaneous IgG4-RD2 and histologic features in accordance with the Comprehensive Diagnosis Criteria of the disease published in 20123 (ie, dense lymphocytic infiltrates occupying the dermis and the hypodermis, storiform fibrosis, and numerous polytypic plasma cells). Moreover, we showed that, more than 40% of plasma cells were IgG4+, and the ratio IgG4/IgG plasma cells was greater than 40% in both patients (76% in one and 100% in the other). Following all these criteria, our cases were indeed consistent with probable IgG4-RD.
Ingen-Housz-Oro S, Ortonne N, Chosidow O. IgG4-Related Skin Disease—Reply. JAMA Dermatol. 2013;149(12):1440. doi:10.1001/jamadermatol.2013.7329