Friday 12 December 2003
Definition: In the OMS classification (2004), Kaposi sarcoma was moved into the category of intermediate vascular tumors (rarely metastasizing) in order to reflect continuing ambiguity as to the precise biological nature of this lesion.
This is a multifocal HHV-8-driven vascular proliferation which does not show conventional features of malignancy—in particular, it may regress spontaneously.
It shows relative sparing of certain tissues such as brain, kidney and skeletal muscle, is most often diploid, is very difficult to transplant/xenograft and does not appear to show any conventional pattern of metastasis.
Human herpesvirus-8 (HHV-8) infection is considered the initiating factor in all forms of Kaposi sarcoma (KS)
No consistent abnormality
- soft tissue tumors
- vascular tumors