The epithelial islets of Malasse

Malasse epithelial islets are microscopic clusters or tracts of epithelial cells that remain in the periodontal ligament after the completion of tooth root formation. They represent fragments of the embryonic root sheath (Gertwig’s sheath).

Etiology and pathophysiology

Normally, these cells are in a “dormant” state and are not active. However, in the development of chronic inflammation at the root apex (apical periodontitis), bacterial products can stimulate these cells to divide. Active reproduction of epithelial remnants is the key mechanism of radicular (root) cyst shell formation.

Clinical significance

Understanding the role of Malasse remnants is critical to the diagnosis of cysts.

The epithelial cells of Malasse islets may secrete factors that resorb bone tissue. To date, there is no direct evidence whether regression of the epithelial lining of the cyst can occur after nonsurgical endodontic treatment. Considering possible pathogenetic mechanisms, epithelial growth may cease after removal of a stimulating bacterial factor, such as after endodontic treatment. Subsequently, the epithelial lining may thin or disappear, creating conditions for healing. Subsequently, if healing of the periapical focus has not occurred, enucleation of the cyst (cystectomy) is performed.