Asymptomatic yellow papule on the left posteriorlateral tongue. (from Color Atlas of Oral and Maxillofacial Diseases)
Small yellow nodule in the tonsillar fossa. (from Color Atlas of Oral and Maxillofacial Diseases)
The oral lymphoepithelial cyst is an uncommon keratin-filled cyst that develops within tonsillar or accessory oral lymphoid tissue. Normal tonsillar tissue is situated immediately beneath the mucosal surface. The surface epithelium typically demonstrates invaginations into the underlying lymphoid tissue, known as tonsillar crypts. An epithelium-lined crypt may fill with keratinaceous debris and form a small keratinfilled cyst that becomes pinched off from the mucosal surface. However, it also has been theorized that some oral lymphoepithelial cysts could arise from excretory salivary gland ducts that either are entrapped within tonsillar tissue or induce an adjacent lymphoid reaction.
Oral lymphoepithelial cysts can occur at any age, but they are diagnosed most frequently in young adults. The lesion appears as a small, white or yellow, pearl-like nodule that is usually less than 1 cm in diameter. Oral lymphoepithelial cysts develop most often in the palatine tonsil or lingual tonsil, although some examples occur in the floor of the mouth in association with accessory lymphoid aggregates. The lesion often is discovered as an asymptomatic incidental finding.
Many oral lymphoepithelial cysts can be diagnosed on a clinical basis with reasonable certainty and may not require biopsy. However, if the diagnosis is uncertain, then conservative excisional biopsy can be performed, and the lesion should not recur.