Oral lymphoepithelial cyst: A clinicopathological study of 26 cases and review of the literature

Abstract

IntroductionΤo describe the clinicopathological features of 26 oral lymphoepithelial cysts (LECs) and review the literature.Material and MethodsTwenty-six cases of oral LECs diagnosed during a 37-year period were retrospectively collected. The patients’ gender and age, as well as the main clinical features of the cysts were retrieved from the requisition forms. The main microscopic features were recorded after reevaluation of all cases. Pubmed and Google Scholar electronic databases were searched with the key word “oral LEC”. Inclusion criteria were the microscopic confirmation of LEC diagnosis and the report at least two of three main clinical features (gender, age and cyst’s location).ResultsThe 26 oral LECs represented 0.08% of 31,564 biopsies accessioned during the study period. They affected 25 patients, 14 females and 11 males with a mean age of 33.04±9.81 years. They appeared as smooth (92%) nodules, with soft (24%) or firm (76%) consistency and normal (28%), yellow to normal (20%), yellow (32%) or white (20%) hue, in the tongue (69.23%) or the floor of mouth (30.77%). They were covered by parakeratinized squamous (92.31%) or non-keratinized (7.69%) epithelium and contained desquamated epithelial cells, amorphous eosinophilic material and/or inflammatory cells (100%). The lymphoid tissue surrounded the cystic cavity partially (34.62%) or completely (65.38%), often in a follicular pattern with prominent germinal centers (53.85%). Literature review yielded 316 cases of oral LECs derived from 25 case reports, 3 case studies/retrospective studies with detailed information for each case and 7 studies with summarized data.ConclusionsOral LEC is a pathologic entity with discrete clinical presentation that is, however, commonly misdiagnosed in clinical practice as other, mostly benign, entities. Its pathogenesis remains obscure, as its clinicopathologic features are consistent with both theories suggested up to date. Key words:Oral lymphoepithelial cyst; developmental cyst; non odontogenic cyst; lymphoid tissue; oral tonsil.

Clinicopathological and immunohistochemical features of the oral lymphoepithelial cyst: A multicenter study

“…Lymphoid follicles of OLEC exhibited ordinary demarcation between B and T cells territories, although most lesions did not have these lymphoid follicles. The connection between the cystic epithelium and overlying mucosa found herein has been reported elsewhere . Taken together, these findings seem to support the theory that OLEC arises from the entrapment of oral epithelium in connective tissue, giving rise to a cystic cavity where lymphoid tissue is normally present .…”

“…The major histopathological description of OLEC is that of a cystic lesion lined by a parakeratinized squamous epithelium that has a flat interface with the cystic wall of fibrous connective tissue in which lymphocytic aggregates are found. The cystic lumen may contain a thick gelatinous whitish‐yellow liquid compatible with keratin, desquamated epithelial cells, and inflammatory cells . We confirm some of these features in the present study but with the following variations: a non‐keratinized epithelium predominated; epithelial hyperplasia was a common finding, blurring the clear separation between the cystic epithelium and the fibrous capsule; lymphoid follicles were not ubiquitously seen in the capsule; and many cases exhibited an evenly organized lymphocytic infiltrate.…”

“…Similarly, the inclusion of epithelium in a peripancreatic lymph node, squamous metaplasia from an obstructed and enlarged intrapancreatic duct, or a misplaced branchial cleft during embryogenesis seems to be involved in the development of lymphoepithelial cysts in the pancreas . Despite the origin of lymphoepithelial cysts in different organs, the pathological findings are similar: a cavity filled with yellowish‐white material, lined with squamous epithelium, and surrounded by lymphoid tissue that may be organized into lymphoid follicles or germinal centers . Lymphoepithelial cysts of the pancreas can present mucinous cells and sebaceous differentiation as well as cholesterol crystals in the lumen as additional findings …”

“…Non‐odontogenic developmental cysts account for less than 1% of all lesions diagnosed at oral pathology services and encompass nasolabial cyst, nasopalatine duct cyst, incisive papilla cyst, oral lymphoepithelial cyst (OLEC), thyroglossal duct cyst, palatal cyst of the newborn, epidermoid cyst, and dermoid cyst …”

“…The frequency of OLEC ranges from 16.4% to 30.99% of all non‐odontogenic developmental cysts . Due to its rarity, few studies have reported a large series of OLEC . Thus, although lymphocytic infiltrate is a prominent microscopic finding of OLEC, its cell composition has not been characterized and no previous studies have described the immunohistochemical features .…”