Lipopigment in odontogenic cysts.

A study of 105 odontogenic cysts revealed the presence of pigmented cells in the cyst wall in 38% of the cases. The frequency of pigmented cells was higher in the inflammatory odontogenic cysts than in the development cysts. Although isolated pigmented cells were seen within the epithelial lining and cyst cavity, the larger collections were closely associated with cholesterol crystals and hemosiderin deposits; they contained light brown cytoplasmic pigment which manifested sudanophilia, acid-fastness, silver reduction capacity, PAS positivity and yellow autofluorescence in ultraviolet light. The morphology, histochemical reactions and autofluorescence suggest that the pigmented cells are macrophages containing ceroids. It has been suggested that the hemosiderin which is found in the cyst wall serves as an oxidation catalyst for the locally liberated lipids, the end result of which is the formation of the ceroid pigment.