Kaposi's sarcoma
Definition
- HHV-8-associated semimalignant tumor of the endothelia of blood and lymphatic vessels with optional visceral dissemination (GI tract with bleeding, lungs, lymph nodes).
- Pathogen: HHV-8 — γ-herpesvirus, obligatory but not sufficient; manifestation only with additional immune dysregulation.
Subtypes
- Classic Type: Risk group Men Mediterranean/Eastern Europe — Localization leg/foot, slow course.
- Endemic Type (African): Sub-Saharan Africa and migrants, legs, nose, oral mucosa, often lymphadenopathic and more aggressive, can affect children.
- Epidemic Type (HIV/AIDS): Localization Face + Genital, mucocutaneous; AIDS-defining at CD4 < 200/µl.
- Iatrogenic Type: Immunosuppression after organ transplantation (calcineurin inhibitors) or with chronic iatrogenic IS — Leg, trunk; Late-stage trigger often CD4 < 200/µl or longer IS duration.
Clinical Presentation & Stages (ACTG)
- Clinical Presentation: livid-violet macules → plaques → nodules along skin cleavage lines, later ulceration / lymphedema. Mucosal involvement (palate, GI) common in epidemic / endemic types.
- Stage I: Characteristic circumscribed cutaneous (< 10 lesions, no LN)
- Stage II: > 10 cutaneous lesions
- Stage III: only visceral manifestation (rarely without skin)
- Stage IV: cutaneous + visceral
- ACTG Classification HIV-KS: Tumor (T0/T1) + Immune status (I0/I1, CD4 < 200) + Systemic illness (S0/S1).
Diagnostics
- Biopsy + Histology + HHV-8-LANA Immunohistochemistry (pathognomonic).
- HIV test obligatory for every KS first-diagnosis patient — always run it!
- Staging Diagnostics: Ultrasound + Chest X-ray — GI and lung involvement are the most common visceral manifestations.
- Histology: spindle cell proliferation with erythrocyte extravasation, "Promontory sign" (protruding endothelial cells project into the lumen), HHV-8-LANA-positive.
Differential diagnoses
- Cutaneous angiosarcoma
- Dermatofibroma
- Haemangioma
- Melanoma
- Pyogenic granuloma
- Dermatofibrosarcoma protuberans
- Port-wine stain
- Amelanotic melanoma
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Note: This page is intended for medical education and does not replace diagnosis or treatment decisions in individual cases. Treatment and follow-up content is available in the app.