A Man with a Chronic Painful Perianal Ulcer

Diagnosis: Perianal amebiasis cutis (Entamoeba histolytica). Examination of biopsy specimens from the perianal ulcer revealed the presence of invasive E. histolytica (figures 1-3). Concurrent colonoscopy findings and examination of rectal biopsy specimens also showed focal proctitis with invasive amebic parasites. No pathologic evidence of Crohn disease or ulcerative colitis was seen. Tests for HIV, Neisseria gonorrhea, Chlamydia trachomatis (including lymphogranuloma venereum serovars), Treponema pallidum, and Herpes simplexhad negative results. The patient's ulcer and symptoms rapidly resolved with a 2-week course of metronidazole. Because the patient was lost to follow-up, he did not receive paromomycin at the end of