In this paper we present a case history of a homosexual HIV-positive male with a painless nodule on the penis. Screening for sexually transmitted diseases did not detect any infection until the node perforated spontaneously. A diagnosis of lymphogranuloma venereum was made when chlamydia trachomatis type L2 DNA was extracted from the lesion. This case illustrates that standard screening may not be sufficient for making the diagnosis of lymphogranuloma venereum. Copyright