AIDS-related Kaposi's sarcoma (KS) is the most common tumor arising in HIV-infected persons and is an AIDS-defining illness. Gastrointestinal (GI) involvement can occur in the presence or absence of cutaneous lesions and patients are often asymptomatic. We describe a case of KS with symptomatic extensive GI involvement after initiation of HAART and corticosteroid therapy. A 36 y/o homosexual Hispanic man with AIDS (CD4 of 31) presented to the ED with painful swallowing, fevers, night sweats and 5 lbs. weight loss over two weeks. He reported 6 months of diarrhea averaging 3 loose stools/day. HAART, high dose steroids, and Valganciclovir were started 4 months prior for AIDS, facial swelling and oral ulcers. Vital signs were T103.6 F, BP 102/54, PR 112, RR 20, and SpO2 of 100%. He had facial edema with violaceous plaques and nodules scattered across his face, dorsal tongue, torso and extremities, and oral ulcers. WBC 0.4 K/uL, Hgb 10.3 g/dL, and albumin of 1.4 g/dL. Antibiotics were given for neutropenic fever. Stool studies were negative for infection; positive FOBT. EGD revealed numerous erythematous nodules in the esophagus, stomach, and duodenum. Colonoscopy showed hemorrhagic nodules throughout the colon with multiple large ulcerations in the ascending colon. Biopsies revealed KS confirmed by human herpes virus 8 (HHV-8) immunostudy; CMV negative. Biopsies of skin and tongue were also positive for KS. Liposomal doxorubicin and filgrastim were started. Bone marrow biopsy was negative for HHV-8, infection, or malignancy. PEG tube was placed for malnutrition. Two cycles of Doxorubicin were completed. Odynophagia, diarrhea, and skin lesions resolved. He now tolerates solid food. KS is a vascular tumor associated with HHV-8. KS incidence significantly declined due to widespread use of HAART. KS usually presents with skin disease but can also involve a wide range of visceral organs including the GI and respiratory tract. Patients with GI involvement are often asymptomatic or may experience weight loss, abdominal pain, nausea and vomiting, GI bleeding, malabsorption, intestinal obstruction, or diarrhea. KS appears as hemorrhagic nodules sometimes with ulcerations. Biopsy shows whorls of spindle-shaped cells with leukocytic infiltration and neovascularization. Systemic chemotherapy is indicated for extensive cutaneous disease, symptomatic visceral disease, or cutaneous disease refractory to local therapy. Corticosteroids and infections have been associated with induction and worsening of preexisting KS. The high incidence of KS immediately following HAART may be due to the severe immunosuppression that led to HAART or to uncovering of KS by the immune reconstitution inflammatory syndrome. Chronic diarrhea in AIDS patients warrants endoscopy to evaluate for infectious causes and other diseases such as KS.Figure 1Figure 2Figure 3