Nodular Kaposi's Sarcoma

Kaposi's sarcoma is an HHV-8 driven angioproliferative disease. Four types are described and include: classic form, endemic, iatrogenic (typically arising in the setting of immunosuppressive drug therapy) and AIDS-associated. Clinically, the lesions can appear red/blue or brown and assume the form of a macule, plaque or nodule. The microscopic appearance is variable and can range from irregular, dissecting vascular channels to sheets of epithelioid or spindled cells with slit like spaces, attendant RBC extravasation and occasional vascular lumens. PAS positive hyaline globules (representing RBC degradation products) and a lymphoplasmacytic infiltrate are commonly seen as well.