Interstitial granulomatous dermatitis associated with primary biliary cirrhosis

Dear Editor, Interstitial granulomatous dermatitis (IGD) is a rare clinical pathological entity, which has various clinical presentations and a peculiar histopathological pattern. IGD is usually associated with autoimmune disorders, such as rheumatoid arthritis and systemic lupus erythematous. Thus, IGD has been considered as a sign of immune dysfunction. Herein, we report a case of IGD with primary biliary cirrhosis (PBC). To our knowledge, this is the first report of IGD associated with PBC. A 65-year-old man presented with a 1-month history of asymptomatic lesions on his upper extremities. On physical examination, he had several coin to egg-sized purplish red plaques of irregular shape on the extensor aspect of the forearms with symmetrical distribution, which were non-scaly and without ulceration or exudation (Fig. 1a). His medical history included a 15-year prostatic hyperplasia, 10-year abnormal liver function and cerebral infarction. His medications included Qian Lie Kang tablets, silybin meglumine tablets and Nao Xue Kang. Laboratory tests revealed that the following markers were abnormal: alanine aminotransferase, 67 IU/L (normal, 0–40); aspartate aminotransferase, 48 IU/L (normal, 0–42); c-glutamyltransferase, 135 IU/L (normal, 0–52); erythrocyte sedimentation rate (ESR), 18 mm/h (normal, 0–15); C-reactive protein (CRP), 5.120 mg/dL (normal, <0.800); immunoglobulin (Ig)G, 2030 mg/dL (normal, 694–1620); IgG3, 86.5 mg/dL (normal, 11–85); IgA, 493 mg/dL (normal, 68–378); IgM, 499 mg/ dL (normal, 60–263); and antinuclear antibody titers, 1:640 dilution (normal, <1:40). Serum tests for antimitochondrial antibody subtype M2 were positive. Tests for hepatitis B surface antigen, anti-hepatitis C virus antibody and anti-HIV antibody were all negative. The findings met the criteria for a diagnosis of PBC. Skin biopsy obtained from one lesion showed a moderately dense, diffuse interstitial infiltration of histiocytes and lymphocytes in the dermis, with some areas of collagen degeneration surrounded by clusters of histiocytes (“floating sign”) (Fig. 1b). There was no infiltration of eosinophils and neutrophils, and no vasculitis. Alcian blue staining was negative (Fig. 1c). Based on these findings, a diagnosis of IGD was rendered. After being diagnosed with PBC, the patient started to receive ursodeoxycholic acid (UDCA), and continued to receive Qian Lie Kang tablets and Nao Xue Kang, but did not use any kind of drugs to treat his skin lesions. After