Myoid cells with clear cytoplasm spinning off of large vessels in a background of mature fat, the classic microscopic features of<unk> <unk> s are tumours consisting of perivascular epithelioid cells (cells which are found surrounding blood vessels and which resemble epithelial cells). A tumour of this kind is known as a PEComa, from the initials of perivascular epithelioid cell. Older literature may classify them as hamartomas (benign tumours consisting of cells in their correct location, but forming a disorganised mass) or choristoma (benign tumours consisting of normal cells in the wrong location). PEComas are themselves a kind of mesenchymal tumour which involves cells that form the connective tissue, cardiovascular, and lymphatic systems. An<unk>  is composed of varying proportions of vascular cells, immature smooth muscle cells, and fat cells. These three components respectively give rise to the components of the name: angio-, myo-, and lip-. The -oma suffix indicates a tumour.<unk> s are typically found in the kidney, but have also been commonly found in the liver and less commonly the ovary, fallopian tube, spermatic cord, palate, and colon. The Maclean imaging classification system for renal<unk> s is based on the location of the<unk>  within the kidney. Since all three components of an<unk>  (vascular cells, immature smooth muscle cells, and fat cells) contain a "second-hit" mutation, they are believed to have derived from a common progenitor cell that suffered the common second-hit mutation.
Angiomyolipoma
Angiolipoma
Myelolipoma
Nephrogenic adenoma
Renal medullary fibroma
Renal oncocytoma
Papillary tumor
Oncocytoma