DP19 Two patients with Kaposi sarcoma from the 2-week-wait clinic

Abstract

Abstract We present two cases of Kaposi sarcoma (KS) in HIV-negative men who have sex with men (MSM) with no coexisting immunosuppressive treatment or conditions. They both presented with suspicious lesions on lower extremities, with no other mucocutaneous involvement. The initial clinical presentation of both patients was atypical, with uncharacteristic aspects of lesions on clinical examination and dermoscopy, which prompted further investigations. Skin biopsies were performed for both patients. Both cases had similar histological findings in keeping with KS: slit-like vascular spaces within the dermis, proliferation of capillary blood vessels with associated inflammatory infiltrate with lymphocytes and plasma cells and focal aggregates of spindle cells. Immunohistochemistry revealed endothelial cells displaying positive staining for human herpesvirus (HHV)-8. Immunodeficiency screening revealed no abnormalities, and repeat HIV screening was negative in both patients. These cases present an interesting occurrence of an increasingly encountered new subtype of KS seen in HIV-seronegative immunocompetent MSM. In addition to the four established variants of KS, this is an emerging variant that arises mostly in middle-aged MSM. HHV-8 has been identified as the aetiological agent in KS; indeed, the viral infection precedes the development of the disease. The fifth subtype is increasingly recognized: nonepidemic KS in MSM who are HIV-negative and have no other causes for immunodeficiency, as seen in our two cases. This subtype has been reported in the literature since the 1980s in this specific population. The clinical presentation resembles classic KS, with predominantly cutaneous involvement of the lower limbs, running a similar indolent course. There is a strong connection between HHV-8 infection and the development of KS; however, in countries where there is a low prevalence of the virus, in the general population, there is increased detection in the MSM group. Correlating the high detection rate of HHV-8 in MSM with its role in the development in KS, immunocompetent MSM are at risk of developing the condition. However, this subtype carries an overall good prognosis, with an indolent course and good response to similar therapeutic options used in the classic subtype.