Kaposi Sarcoma of the Medial Foot in an MSM, HIV-Negative Man: A Fifth Clinical Variant

Kaposi sarcoma (KS) is a low-grade vascular neoplasm with four well-documented clinical types: classic, African (endemic), acquired immunodeficiency syndrome (AIDS)-associated (epidemic), and iatrogenic, as well as a fifth recently described variant, men having sex with men (MSM) without human immunodeficiency virus (HIV) infection. Often distinguishable on clinical exam, KS lesions are typically found on the skin and mucosa of immunocompromised individuals, though numerous published reports have demonstrated the ability of KS to present in immunocompetent individuals. Here, we present the case of a 66-year-old, HIV-negative MSM with violaceous, non-blanching macules and patches of the medial foot referred to dermatology by his primary care physician. Histopathologic analysis revealed Kaposi sarcoma. Although this patient engaged in same-sex sexual behaviors, his HIV-negative status and otherwise lack of immunocompromise would deter many clinicians from suspecting a diagnosis of KS. Despite therapy, disease prognosis is often dependent upon stage at diagnosis. Therefore, it is important that every clinician understand the cutaneous findings associated with KS and be aware of the higher rates of KS even in HIV-seronegative MSM to facilitate prompt diagnosis and immediate treatment of this high-risk population.