P1744 - Gastrointestinal Kaposi Sarcoma: A Rare Case of an Isolated Rectal Lesion in an Immunocompetent HIV-Negative Patient

Andy Silva-Santisteban, MD¹, Sultan Mahmood, MD², Wilfor J. Diaz Fernandez, MD³, David Rodriguez Falla, MD⁴, Samuel Igbinedion, MD⁵, Erik Holzwanger, MD², Gamze Ayata, MD², Harry Rosenberg, MD², Poojaben Dhorajiya, MD², Mandeep Sawhney, MD, MS², Douglas Pleskow, MD, FACG³, Moamen Gabr, MD, MSc,², Tyler Berzin, MD, FACG^2
1Beth Israel Deaconess Medical Center, Brighton, MA; ²Beth Israel Deaconess Medical Center, Boston, MA; ³BIDMC, Boston, MA; ⁴Hospital Almenara, Lima, Lima, Peru; ⁵Center for Advanced Endoscopy, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA

Introduction: Kaposi sarcoma (KS) is an endothelial growth associated with Human Herpes Virus-8 (HHV-8). KS primarily affects the skin; however, gastrointestinal (GI) lesions can be seen in immunocompromised patients. KS presents in 4 clinical forms (endemic, iatrogenic, classic and HIV-associated). Clinical presentation in HIV-negative men who have sex with men (MSM) resembles the classic form, limited to cutaneous or disseminated disease. We report a case of an isolated GI KS in a healthy patient who does not meet criteria for any KS clinical variants.

Case Description/Methods: A 61-year-old HIV-negative man on Pre-Exposure Prophylaxis (PrEP) for HIV and sexual history of MSM presented for a screening colonoscopy. The patient denied symptoms like abdominal discomfort, melena, hematochezia, weight loss, drug consumption or travel outside the US.

Systemic evaluation ruled out associated skin lesions, lymphadenopathies or organomegaly. Routine blood tests were within normal limits. HIV serology, Hepatitis C Virus antibody, gonorrhea & chlamydia PCR, and syphilis serology were negative. An HIV RNA quantitative real-time PCR was also negative.

The colonoscopy showed a single sessile 6 mm nodule of benign appearance in the distal rectum, which was endoscopically resected (Fig.1, A). Pathology demonstrated atypical spindle cell proliferation forming slit-like vascular channels most consistent with Kaposi sarcoma. Immunohistochemistry was positive for CD31 and CD34. HHV8 was also positive in a large population of lesional cells (Fig.1, B and C). To assess for any other lesions, a PET/CT was ordered; however, no other suspicious uptake outside the rectum was found. The patient is currently followed longitudinally by oncology and gastroenterology every 6 months.

Discussion: Isolated GI KS has been reported as a manifestation of HIV/AIDS related-KS or iatrogenic-KS. Sporadic cases in immunocompetent HIV-negative patients have been considered unusual or initial forms of classic KS. Based on clinical KS classification, we present a unique case of an isolated KS lesion in the rectum that does not match the traditional forms of this disease. In previous cases of HIV-negative MSM with KS, a second neoplasia was found in 14%; therefore, FDG PET/CT and proper follow-up are key to assessing KS's potential systemic progression. One year after diagnosis, our patient remains disease-free after resection of rectal nodule.



Disclosures:


Andy Silva-Santisteban, MD¹, Sultan Mahmood, MD², Wilfor J. Diaz Fernandez, MD³, David Rodriguez Falla, MD⁴, Samuel Igbinedion, MD⁵, Erik Holzwanger, MD², Gamze Ayata, MD², Harry Rosenberg, MD², Poojaben Dhorajiya, MD², Mandeep Sawhney, MD, MS², Douglas Pleskow, MD, FACG³, Moamen Gabr, MD, MSc,², Tyler Berzin, MD, FACG². P1744 - Gastrointestinal Kaposi Sarcoma: A Rare Case of an Isolated Rectal Lesion in an Immunocompetent HIV-Negative Patient, ACG 2023 Annual Scientific Meeting Abstracts. Vancouver, BC, Canada: American College of Gastroenterology.