INTESTINAL SPIROCHETOSIS AND ACQUIRED-IMMUNODEFICIENCY-SYNDROME - ULTRASTRUCTURAL STUDIES OF 2 CASES

Two cases of intestinal spirochetosis (IS) with acquired immunodeficie ncy syndrome are reported. In case 1, a 48-year-old homosexual black m an presented with a 1-month history of alternating watery diarrhea and constipation, which dissipated following the removal of two colonic h yperplastic polyps containing IS. In case 2, a 26-year-old homosexual black man presented with a 3-month history of persistent bloody diarrh ea and was found to have chronic shigellosis and IS. Pathologic findin gs of IS were similar in both cases. Basophilic fringes typical of IS covered the surfacing colonic epithelium and consisted of dense growth s of spirochetes adherent to and oriented perpendicular to the plasma membranes of the surfacing epithelium. The spirochetes measured 3 to 5 mu m in length and 0.2 mu m in width, contained four to eight axial f ibrils, and closely resembled Brachyspira aalborgi ultrastructurally. These cases are notable because the histopathologic changes of IS were more extensive than generally described. There was involvement of bot h the right colon and rectum by IS in case 2, and in both cases there was extension of the IS down into the crypts of Lieberkuhn, spirocheta l invasion of the colonic mucosa, and a conspicuous inflammatory respo nse by macrophages in the underlying lamina propria.