A 67-year-old woman was admitted to our hospital because of a complete right bundle branch block. She had been treated with minocycline for skin sarcoidosis and her symptoms had ameliorated four years previously. Gallium scintigraphy revealed an abnormal uptake in the heart but not in the skin or lungs. She was diagnosed with cardiac sarcoidosis, although an endomyocardial biopsy could not detect any sarcoid lesions. Immunohistochemical staining for Cutibacterium acnes was positive for granulomas of the skin lesions which had been previously biopsied. One year after starting the administration of steroids, her condition improved.
Keywords: antibiotics; biopsy; cardiomyopathy; immunostaining; steroid.