Inflammation in the fat layer usually gives rise to a septal or lobular panniculitis histological picture or a mixture of both.
Infiltrates of cells and sustances can also occur in the fat layer and some deep infections with deep fungii or atypical mycobacteria can mainly be found in the fat layer.
We will discuss each of these below.
The Clinical Mnemonic is PMLE ( Pancreatic, Metabolic and Mycobacterial, Lupus erythematosus and Erythema nodosum)