Nodular tertiary syphilis mimicking granuloma annulare

We describe a 47-year-old man with annular plaques on the arms and torso th at were treated as granuloma annulare, based on clinical and histopathologi c findings. Exacerbation of the lesions during treatment with topical corti costeroids prompted a search for an infectious cause, which proved to be sy philis in the tertiary stage. The clinician should maintain a high index of suspicion for syphilis in the differential diagnosis of unusual annular sk in lesions in a patient with noncaseating granulomas seen on skin biopsy.