Kaposi sarcoma is highly associated with patients with retroviral disease, typically involving the skin. It is a low-to-intermediate grade mesenchymal tumor that involves the lymphovascular system.

Rarely it occurs in other organs, such as the lungs.

On CT chest ill-defined (flame-shaped) nodular opacities with a bilateral and roughly symmetrical perilymphatic and peribronchovascular distribution have been documented.  However, a range of other findings are also described, such as focal groundglass change and interlobular septal thickening.