Lymphoepithelial Cyst in the Palatine Tonsil

A Retrospective Clinico-Pathological Analysis with Review of Literature of Oral and Cervical Lympho-Epithelial Cysts from a Pathological Perspective

Oral and cervical lympho-epthelial cysts (LECs) are uncommon lesions with histopathological similarities. The aim of the study is to present clinico-pathological characteristics of oral and cervical LECs with a review of literature in order to create awareness on this uncommon entity. Eighteen new cases of oral and cervical LECs obtained from the archives of the University of Peradeniya and University of Geneva were used for the clinico-pathological analysis. The average age at diagnosis of 7 oral and 11 cervical LECs were 40 and 36 years, respectively. Both showed a female predilection (male:female ratio at 3:4 and 4:7, respectively). The only difference was found in the size of the lesions with oral LECs being significantly smaller than cervical LECs (0.9 cm vs. 4.6 cm). LECs may clinically resemble neoplasms (4/18), including malignancies (1/11 in the present series). None of the 18 LECs recurred following surgical removal. The literature-review-based analysis of 514 oral LECs confirms that the lesions are observed predominantly in adults in 4th–5th decades of life and are relatively small lesions of less than 2 cm in diameter. Oral LECs were found to occur predominantly in the tongue and floor of the mouth, similar to 88% of lesions in literature. In conclusion, oral and cervical LECs are two histologically similar cysts that occur in two distinct sites. The literature review supports the information observed in our study with respect to age of occurrence, site predilections, and size. Cervical LECs, particularly the ones that occur in the parotid region, may require further investigations to exclude BLEL of parotid gland, which occur in HIV infected patients.

Derivation of thyroid lymphoepithelial cysts from follicular cells

The pathogenesis of thyroid lymphoepithelial cysts is controversial, and two hypotheses have been proposed, namely derivation from branchial-derived remnants or from squamous metaplasia of the follicular cells. The aim of this study was to clarify the pathogenesis of thyroid lymphoepithelial cysts. We performed pathological and immunohistochemical examination of 21 thyroid lymphoepithelial cysts, 13 non-neoplastic squamous metaplasia samples without thyroid carcinoma, 13 solid cell nests, and 14 lateral cervical cysts. On ultrasound, half of thyroid lymphoepithelial cysts were interpreted as calcified nodules regardless of no calcification. Thyroid lymphoepithelial cysts and squamous metaplasia tended to be located in the central and lower portions of the thyroid, while solid cell nests were located in the upper and central portions (p < 0.05). In 95.2% of patients with thyroid lymphoepithelial cysts and all patients with squamous metaplasia, lesions were histologically associated with chronic thyroiditis forming lymph follicles. Hashimoto's disease was serologically confirmed in 18 patients with lymphoepithelial cysts (85.7%) and 10 patients with squamous metaplasia (76.9%). Immunohistochemically, lymphoepithelial cysts showed nuclear positivity for PAX8, thyroid transcription factor 1, and p63. One lateral cervical cyst (7.1%) showed positive staining for PAX8, while solid cell nests were PAX8-negative. In three (14.3%) cases of thyroid lymphoepithelial cysts, squamous cells located on the superficial layer were focally and weakly positive for CEA. We concluded that thyroid lymphoepithelial cysts originate from follicular cells and are unrelated to solid cell nests and lateral cervical cysts arising from branchial-derived remnants.

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

Introduction

Τo describe the clinicopathological features of 26 oral lymphoepithelial cysts (LECs) and review the literature.

Material and Methods

Twenty-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).

Results

The 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.

Conclusions

Oral 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.