Kaposi Sarcoma Flashcards
What is Kaposi Sarcoma (KS)?
A vascular tumor associated with infection by Human Herpesvirus-8 (HHV-8), characterized by proliferation of endothelial cells, inflammatory infiltrates, and angiogenesis.
What are the main types of Kaposi Sarcoma?
Classic KS: Occurs in elderly individuals, especially men of Mediterranean or Eastern European descent.
Endemic (African) KS: Seen in sub-Saharan Africa, not always associated with HIV.
Epidemic (AIDS-associated) KS: Linked to HIV/AIDS and immunosuppression.
Iatrogenic (Immunosuppressive therapy-associated) KS: Occurs in patients on immunosuppressive therapy, such as organ transplant recipients.
Which type of KS is most aggressive?
Epidemic (AIDS-associated) KS.
What virus is associated with Kaposi Sarcoma?
Human Herpesvirus-8 (HHV-8), also known as Kaposi Sarcoma-associated herpesvirus (KSHV).
How does HHV-8 contribute to the pathogenesis of KS?
HHV-8 infects endothelial cells, causing genetic alterations that promote proliferation and angiogenesis.
Viral proteins mimic cellular growth factors, enhancing tumor formation.
The immunosuppressed state (e.g., HIV) reduces control over HHV-8 replication.
What are the key factors that promote KS development?
Immunosuppression (e.g., HIV/AIDS, organ transplantation).
Chronic inflammation.
HHV-8 infection.
What are the characteristic skin lesions in Kaposi Sarcoma?
Red, purple, or brown macules, plaques, or nodules.
Lesions may be asymptomatic or tender and may ulcerate.
Often found on the lower extremities, face, oral cavity, or genitalia.
What is the pattern of lesion distribution in AIDS-associated KS?
Often widespread, involving the skin, mucous membranes, and internal organs.
What symptoms are seen with visceral involvement in KS?
Gastrointestinal (GI): Bleeding, obstruction, or diarrhea.
Pulmonary: Dyspnea, cough, hemoptysis, and pleural effusion.
How does endemic KS differ from classic KS?
Endemic KS may affect younger individuals and is more likely to involve lymph nodes and internal organs.
How is Kaposi Sarcoma diagnosed?
Clinical examination: Appearance and distribution of characteristic lesions.
Biopsy: Confirms diagnosis; histology shows spindle cells, slit-like vascular spaces, and extravasated red blood cells.
What is the role of immunohistochemistry in diagnosing KS?
Detection of HHV-8 latent nuclear antigen (LANA-1) confirms the presence of HHV-8.
What imaging studies are used for visceral involvement in KS?
Chest X-ray or CT: For pulmonary KS.
Endoscopy or colonoscopy: For gastrointestinal KS.
What is the cornerstone of treatment for AIDS-associated Kaposi Sarcoma?
Initiation or optimization of antiretroviral therapy (ART) to improve immune function.
What are the primary treatment options for localized KS lesions?
Cryotherapy or surgical excision.
Intralesional chemotherapy (e.g., vinblastine).
Radiation therapy for symptomatic or cosmetically concerning lesions.
