<unk>  refers to little knots of capillaries in various organs.
These tend to be cavernous hemangiomas, which are sharply defined, sponge-like tumors composed of large, dilated, cavernous vascular spaces.
Angiomatosis
Thrombosis
Cavernous transformation
Thrombotic lesion
Granuloma
Pseudoaneurysm
Atherosclerosis
Arterial thrombosis