Contributed by Akosua B Domfeh, MBchB and Alyssa Krasinskas MD
Published on line in June, 2004
The patient was an African-American male in his 20s with a history of HIV infection, who presented with diarrhea, weight loss, and abdominal pain. On colonoscopy, multiple serpiginous ulcers with overlying exudate were found throughout the colon, but predominantly in the left and transverse colon. Serial biopsies from the colonic mucosa and from the margins of several of the ulcers were taken and sent to pathology. These biopsies were obtained in the left, transverse and right colon. The terminal ileum was also intubated and the ileal mucosa was normal in appearance. Biopsies of the ileal mucosa were taken and sent to pathology.
Hematoxylin and eosin stained (H&E) sections of the colon biopsies showed a single fragment of inflamed granulation tissue (Figure 1). No viral inclusions were seen. Fragments of intact colonic mucosa showed minimal crypt architecture distortion and mildly increased lamina propria inflammation composed of lymphocytes, plasma cells, and eosinophils (Figure 2). A neutrophilic exudate was also seen (Figure 3). In addition, in scattered foci, the surface epithelium appeared to be coated by a fuzzy, blue-purple, hematoxyphilic layer (Figure 4). The terminal ileum biopsy showed normal small intestinal mucosa.
An immunohistochemical stain for Cytomegalovirus (CMV) showed rare positive cells within the granulation tissue (Figures 5 and 6). These cells were not readily apparent on the H&E stain.
A Steiner silver stain demonstrated numerous positive (black) organisms attached to the colonic mucosal surface, corresponding to the blue-purple fuzzy layer that was seen on the H&E stain (Figures 7 and 8).