Cutaneous sarcoidosis with livedoid lesions: Evidence of the involvement of Propionibacterium acnes

Dear Editor, Cutaneous sarcoidosis shows variable manifestations, but livedoid lesions are rare. We report such an unusual case and demonstrate the involvement of Propionibacterium acnes that has been currently suspected to cause sarcoidosis. A 25-year-old otherwise healthy woman presented with a 2month history of asymptomatic livedoid lesions on the lower legs (Fig. 1a). Basic blood examinations were unremarkable, and antinuclear antibody and antineutrophil cytoplasmic antibodies were negative. Histopathology showed disseminated small non-caseating epithelioid cell granulomas surrounding the vessels in the entire dermis (Fig. 2a). Many of these vessels showed fibrin deposits, and inflammatory cell infiltrates were scarce (Fig. 2b). Chest computed tomography demonstrated bilateral hilar lymphadenopathy and pulmonary parenchymal infiltrates. Transbronchial lung biopsy (TBLB) revealed epithelioid cell granulomas. The serum levels of angiotensin-converting enzyme (21.6 IU/L; normal, 8.3–21.4) and lysozyme (16.5 lg/mL; normal, 5.0–10.2) were elevated. The patient was thus diagnosed with sarcoidosis. There was no evidence of ocular or cardiac involvements, and systemic treatment was not initiated because of lack of respiratory symptoms. While the livedoid lesions subsided spontaneously within 2 months, infiltrated erythematous plaques developed on the upper legs, waist, lower back and lower arms (Fig. 1b). The subsequent skin biopsy showed epithelioid cell granulomas without obvious angiocentric distribution in the lower dermis and subcutaneous tissue (Fig. 2c). Immunohistochemistry with PAB antibody, a novel monoclonal antibody specific for P. acnes reacting with cell-membrane-bound lipoteichoic acid, detected P. acnes within the granuloma macrophages and giant cells, equally in the livedoid lesion (Fig. 2d), the plaque lesion and TBLB samples. The patient had a history of mild acne but required no medical treatments. We started oral minocycline at 100 mg daily and topical application of corticosteroid and tacrolimus. The cutaneous lesions disappeared within 6 months, and minocycline was stopped. In contrast, the lung lesion has been persistent for over 1 year. Granulomatous vasculitis and microangiopathy may be found frequently by thorough histopathological evaluation of