EP421 - Misdiagnosed: Sigmoid Perforation Secondary to Visceral Kaposi Sarcoma

Purpose/Background: Large bowel perforations are a surgical emergency, with a mortality rate higher than 15%. Common etiologies include both benign and malignant causes. Kaposi sarcoma, a vascular neoplastic process caused by human herpesvirus 8 (HHV8), is classified as an AIDS-defining malignancy. While most patients with Kaposi Sarcoma present with cutaneous manifestations, visceral involvement is rare. It typically presents with abdominal pain, diarrhea, and gastrointestinal bleeding. We present an unusual and rare case of visceral Kaposi sarcoma presenting with sigmoid perforation.

Methods/Interventions: n/a

Results/Outcomes: Our patient is a 53 year-old male with past medical history significant for HIV diagnosed ten years prior with initiation of highly active anti-retroviral therapy (HAART) one month prior to presentation. He initially presented to the outpatient clinic with constipation, abdominal pain, and a 31-pound weight loss over the last several months. A CT scan was performed outpatient and demonstrated mural thickening and induration with stool-filled colon consistent with stercoral colitis. A large polyploid lesion was identified at the rectosigmoid junction on cross-sectional imaging. Flexible sigmoidoscopy revealed a stenosis 10-35cm from anus. Biopsies were obtained and resulted as inflammatory changes and negative for malignancy. He was referred to gastroenterology and initiated on steroids with concerns for inflammatory bowel disease. He subsequently presented to the emergency department a week later with 1 day of abdominal pain, nausea, vomiting. An upright chest x-ray was performed and noted to have free air under the right hemidiaphragm. The patient had normal vital signs but was peritonitic on exam. Given his clinical exam and radiologic findings, he was taken urgently to the operating room for an exploratory laparotomy. He was noted to have feculent ascites secondary to a 1cm sigmoid perforation. We resected the perforation as well as the sigmoid stricture and performed a Hartmann’s Procedure. His post-operative course was complicated by a prolonged ileus, which resolved on post-operative day (POD) 7, and a surgical site infection of E. coli and P. aeruginosa which resolved with incision and drainage supplemented by antibiotics. Notably, while inpatient, the patient’s CD4 count was 34. While inpatient, his pathology resulted as Kaposi sarcoma in colonic mucosa superficially invading muscularis propria with 4 lymph nodes negative for malignancy. He was evaluated by both infectious disease and hematology-oncology teams who recommended outpatient follow up and he was successfully discharged on POD9.

Conclusion/Discussion: We present a rare case of a sigmoid perforation secondary to visceral Kaposi sarcoma, initially misdiagnosed as an inflammatory stricture. In patients who present with colonic strictures, this case highlights the importance of obtaining a thorough history and physical exam for signs of potential malignancies. Additionally, our patient highlights the important role of HAART in the treatment of HIV and AIDS. Without these therapies, AIDS can lead to life-threatening complications such as obstructing visceral Kaposi sarcoma.

Figure 1: Endoscopic and Cross-Sectional Imaging of a patient with visceral Kaposi’s Sarcoma.
A) Flexible sigmoidoscopy with 10cm polypoid mass causing a stricture approximately 20cm proximal to the anal verge. B) Axial and C) Coronal cross-sectional imaging of the polypoid lesion causing partial large bowel obstruction in our patient.