A Rare Constellation of Triple Cutaneous Malignancies With Sustained Therapeutic Response: Kaposi Sarcoma, Basal Cell Carcinoma, and Cutaneous Squamous Cell Carcinoma in a Single Patient

The simultaneous occurrence of three distinct cutaneous malignancies - Kaposi sarcoma (KS), basal cell carcinoma (BCC), and cutaneous squamous cell carcinoma (cSCC) - in a single patient is exceptionally uncommon. We report the case of an 83-year-old male with cardiovascular comorbidities who was diagnosed with KS following histopathological confirmation (CD34⁺, ERG⁺, HHV-8⁺) and had a prior history of excised BCC and cSCC of the skin between 2020 and 2022. Over the course of his illness, he underwent multiple surgical resections, axillary lymph node dissection, systemic chemotherapy with paclitaxel, and immunotherapy. Despite eventual disease progression, he achieved sustained therapeutic benefit for more than 18 months, with clinical stabilization of lesions and meaningful palliation. This rare constellation underscores the diagnostic and therapeutic challenges of managing multiple primary skin malignancies in an immunosenescent patient. The coexistence of KS with keratinocyte carcinomas may reflect overlapping carcinogenic mechanisms, including viral oncogenesis (human herpesvirus-8 (HHV-8)), ultraviolet exposure, and immune dysregulation. Vigilant lesion-by-lesion biopsy, histopathological confirmation, and individualized multimodal management can achieve durable disease control and improved quality of life, even in elderly patients with complex dermatologic oncologic presentations.