Is the real issue the definition of what is K.S.? In other words, if the definition of K.S. is broadened to include all kinds of vascular lesions, even subacute ones, the likelihood that they were not associated with HHV-8 would increase, right? Yes, the definition of Kaposi's sarcoma (KS) is central to whether HHV-8 (KSHV) is always found in these lesions. Currently, KS is specifically defined as a low-grade vascular tumor (neoplasm) that is characteristically associated with HHV-8 infection. This association is now so strong that detection of HHV-8 (often by immunohistochemistry for the LANA-1 protein or by PCR) is often used to confirm the diagnosis of KS and distinguish it from other vascular lesions. If the definition of KS were broadened to include all kinds of vascular tumors or lesions—even ones that are not neoplastic or truly malignant, such as benign vascular proliferations, subacute inflammatory lesions, or other non-HHV-8–related conditions—the likelihood of finding ...