Lipomas may be solitary or multiple, and generally affect the trunk and upper aspects of the limbs.  

Most lipomas are discrete and cured by simple excision, but infiltrative examples that are difficult to excise adequately are occasionally encountered.  

Whether infiltrative or not, lipomas never metastasise. Cytologically well differentiated adipocytes (which are no different cytologically from normal adipocytes) are observed with a lipid laden cytoplasm (unilocular) and a small peripheral nucleus.

They maybe in sheets as on the right of the picture, in clusters or individualised as in the left hand side of the picture.

See Liposarcoma for the malignant variant.

Free lipid is often seen as well as ruptured adipocytes (sometimes difficult to interpret).

First published: Wed, Oct 6 2010