Human herpesvirus-8 positive iatrogenic Kaposi's sarcoma in the setting of refractory ulcerative colitis

Figure 1 Colonoscopy, histologic and immunohistochemistry. A: A colonoscopy was performed following resolution of acute diverticulitis, revealing a tumor in the rectum. Biopsies of the colon revealed distal focal active colitis as well as more proximal crypt architectural irregularities and paneth cell metaplasia consistent with quiescent colitis; B: A colonoscopy was performed following resolution of acute diverticulitis, revealing a tumor in the rectum. Biopsies of the colon revealed distal focal active colitis as well as more proximal crypt architectural irregularities and paneth cell metaplasia consistent with quiescent colitis; C: Histologic sections of the rectal tumor demonstrated a cytologically bland spindle cell proliferation interspersed by irregular vascular spaces containing extravasated erythrocytes (2 ×); D: Histologic sections of the rectal tumor demonstrated a cytologically bland spindle cell proliferation interspersed by irregular vascular spaces containing extravasated erythrocytes (4 ×); E: Histologic sections of the rectal tumor demonstrated a cytologically bland spindle cell proliferation interspersed by irregular vascular spaces containing extravasated erythrocytes (10 ×); F: By immunohistochemistry, the lesional cells were strongly positive for human herpesvirus-8 and consistent with Kaposi’s sarcoma (4 ×); G: By immunohistochemistry, the lesional cells were strongly positive for human herpesvirus-8 and consistent with Kaposi’s sarcoma (10 ×).