Pathogenesis
Three theories explain cyst cavity formation: (1) nutritive theory — central epithelial cells undergo necrosis due to inadequate nutrition and form a cavity; (2) abscess theory — a microabscess forms in the granuloma and becomes lined by proliferating epithelium; (3) secretory theory — epithelial lining secretes products that accumulate, forming the cystic cavity.
The cyst cavity is lined by non-keratinized stratified squamous epithelium and filled with fluid containing desquamated epithelial cells, cholesterol crystals (from breakdown of cellular membranes), albumin, and immunoglobulins.
Cyst expansion is driven by osmotic pressure from the protein-rich cystic fluid drawing water in, hydrostatic pressure from the fluid, and prostaglandin-mediated bone resorption at the periphery.
The fibrous connective tissue wall contains chronic inflammatory cells — plasma cells, lymphocytes, and macrophages — maintaining the inflammatory stimulus.