## 1 Introduction  
The lympho-epithelial cysts (LECs) may occur within the oral cavity or in the cervical region. Irrespective of the site of occurrence, both show similar histopathology [1; 2; 3; 4]. The cervical LECs were initially referred to as Branchial cysts or Branchial cleft cysts [5; 6; 7]. However, as the origin of these cysts remain unclear, current terms based on referring to site of occurrence and histopathological presentation seem more appropriate. The oral LEC is a rare asymptomatic lesion that appears as a whitish or yellowish sub-mucosal nodule that is generally smaller than 1 centimeter and mobile on palpation. It is found mainly on the floor of the mouth and the lateral border of the tongue. In addition, it can also develop in various intraoral locations such as the buccal vestibule and also the soft palate [4]. Two main theories have been proposed concerning the pathogenesis of the LEC. [PERSON]'s theory [1] suggests that the obstruction of lymphoid crypts induces dilatation and cystic proliferation of the epithelium. [PERSON] and [PERSON]'s [2] and [PERSON]'s theories [3] assume that cystic proliferation occurs from epithelial cells that persist in lymphoid tissue during embryogenesis. However, both theories fail to explain how oral LECs occur in sites without lymphoid tissue. The prevalence of oral LECs is difficult to assess because a large number of cases are probably not histopathologically diagnosed, as they are asymptomatic. According to [PERSON] [4], the age of onset is about 45 years with a female predilection (2:1). The clinical diagnosis of the oral LEC is not obvious. It may be confused with an oral muccele, a lipoma, and possibly a tumor of the minor salivary glands, but never as a malignancy. The literature indicates that cervical LECs, on the other hand, appear late in childhood or in young adults, generally as a unilateral asymptomatic mass of slow evolution, localized in the anterior triangle of the neck in the superior third of sternocleidomastoid muscle [5; 6; 7]. The hypotheses of etiopathogenesis of the cervical LECs indicate that they may arise as a result of an anomaly of fusion of the branchial arches [5], a cystic change of thymic origin [6], or a cystic change in cervical lymph nodes [7], of which the first origin is more widely accepted [5]. In support of the above conclusion, it can be stated that branchial anomalies are frequent and represent about 17% of the cervical masses in pediatric consultations [8]. These abnormalities include cervical lympho-epithelial cysts, but also sinuses and fistulae. Regarding gender distribution, [PERSON] et al. [9] and [PERSON] et al. [10] have observed more cases in women than in men, while [PERSON] et al. [11] observed the opposite. [PERSON] et al. have observed dominance on the right side [6] and [PERSON] et al. on the left side [12]. Literature reveals a wide range of clinical differential diagnoses for cervical LECs, including infections such as tuberculous lymphadenitis, and benign and malignant neoplasms including lipoma, neurofibroma, haemangioma, lymphangioma, carotid body tumours, metastatic neoplasms, lymphomas, teratoma, and parotid neoplasms [13], which may require different management strategies. The cervical LEC is generally asymptomatic. Nevertheless, during super infection, the patient may complain of dysphagia, dyspnea, cough, and dysphonia, depending on the size and location of the cyst. Accurate histopathological diagnosis is necessary to ensure proper treatment. The treatment of both oral and cervical LEC is surgical excision [4; 9; 10; 11; 12; 13; 14; 15]. The aim of the present study is to give a clinico-pathological analysis of 18 new cases of LECs. Our data were compared with those of the literature in order to get a better understanding of the oral and cervical LECs so as to improve the clinical and histopathological diagnoses. The rationale for conducting the study was to highlight the comparison between oral and cervical LEC.