Introduction: Kaposi sarcoma (KS), a malignancy originating from endothelial cells and linked to human herpesvirus 8 (HHV-8), disproportionately affects individuals with human immunodeficiency virus (HIV). Despite decreased incidence in high-income countries due to antiretroviral therapy, KS remains a significant concern in sub-Saharan Africa. This article presents a case study of an HIV-positive patient treated exclusively with radiation therapy and provides a comprehensive literature review on KS management. Case Presentation: A 46-year-old HIV-positive patient, under well-controlled infection, exhibited nodular skin lesions, hyperpigmentation, and lymphedema primarily on the lower left limb. Histological analysis confirmed the diagnosis of KS. The patient underwent radiation therapy (36 Gy in 12 sessions) with subsequent topical imiquimod. Nine months post-treatment, no nodular lesions were observed, indicating a positive response. Conclusion: In the antiretroviral era, radiation therapy emerges as a crucial loco-regional treatment in the multimodal management of epidemic KS. With a focus on controlling disease within irradiated areas, excellent response rates and acceptable toxicity levels highlight the efficacy of this approach.