Kaposi sarcoma — SCE Dermatology MCQ

Correct answer: B — Human herpesvirus 8 in immunosuppression

The correct answer is B, human herpesvirus 8 in immunosuppression. This man's violaceous macules and nodules on the legs and hard palate, together with weight loss, oral candidiasis (suggesting advanced HIV with CD4 depletion), the dermoscopic rainbow (polychromatic) pattern, and biopsy showing spindle-cell vascular proliferation are the classic clinical, dermoscopic and histological triad of Kaposi sarcoma. Kaposi sarcoma is caused by human herpesvirus 8 (HHV-8) infecting endothelial and spindle cells, with disease expression driven by the degree of immunosuppression, most often HIV-related but also seen with iatrogenic immunosuppression. Palate involvement and systemic symptoms in this context strongly point to HIV-associated (epidemic) Kaposi sarcoma rather than the classic, endemic or transplant-associated variants seen in immunocompetent patients. Why the other options are wrong: C. Cutaneous infection with Epstein-Barr virus: EBV drives other lymphoproliferative and epithelial malignancies (for example nasopharyngeal carcinoma, some lymphomas) but is not the causative agent of the spindle-cell vascular proliferation seen in Kaposi sarcoma. E. Chronic venous hypertension alone: this causes stasis changes, lipodermatosclerosis or venous ulcers, not violaceous mucocutaneous nodules with spindle-cell vascular histology or a rainbow dermoscopic pattern. A. Dermal deposition of amyloid protein: amyloidosis produces waxy papules or purpura from vessel wall fragility, not a spindle-cell vascular tumour, and does not explain the oral candidiasis or weight loss. D. Type I hypersensitivity to oral Candida: this is an immediate IgE-mediated reaction pattern (urticaria, anaphylaxis), not a mechanism for neoplastic vascular proliferation; the candidiasis here is simply a marker of immunosuppression, not causative of the skin lesions. Key point: violaceous skin and palate lesions with a dermoscopic rainbow pattern and spindle-cell histology in an immunosuppressed (often HIV-positive) patient are diagnostic of HHV-8-driven Kaposi sarcoma.

Reference: DermNet NZ, Skin conditions and HIV/AIDS: A Complete Overview, https://dermnetnz.org/topics/skin-conditions-relating-to-hiv-infection