The expression of cytokeratin in keratocystic odontogenic tumor, orthokeratinized odontogenic cyst, dentigerous cyst, radicular cyst and dermoid cyst

Abstract

The epithelial lining of odontogenic keratocysts exhibits either parakeratosis or orthokeratosis. In 2005, the WHO classified odontogenic keratocysts with parakeratosis as keratocystic odontogenic tumors (KCOT). Odontogenic keratocysts with orthokeratosis were not classified as odontogenic tumors, but instead referred to as orthokeratinized odontogenic cysts (OOC). To clarify the difference between these two lesions, we investigated their biological characteristics using immunohistochemical studies for cytokeratins (CK) in KCOT and OOC as well as in dentigerous cysts (DC), radicular cysts (RC) and dermoid cysts (DMC). We examined twenty-five cases of KCOT, fifteen cases each of OOC, DC and RC, and ten cases of DMC. We studied the immunohistochemical expression of CK10, 13, 17 and 19. To evaluate the immunohistochemical staining pattern, we divided the epithelial lining of the lesions into three layers (surface layer: su, spinous layer: sp, basal layer: ba). For CK10, most OOC and DMC specimens of su and sp were positive. For CK13 and 19, most KCOT, DC and RC specimens of su and sp were positive. For CK17, most KCOT specimens of su and sp were positive. The percentages of total CK expression of su and sp, and ba of CK19 differed significantly between the lesions (P < 0.001). These results support the hypothesis that OOC originate from not the odontogenic apparatus, but the oral epithelial component.

Comparative study of cytokeratin and langerin expression in keratinized cystic lesions of the oral and maxillofacial regions

“…CK13 (54 kDa) is present in the suprabasal layer of oral stratified squamous epithelium (23) and is expressed in odontogenic cysts and tumors (24)(25)(26). However, Tsuji et al (27) and Hayashi et al (28) reported that CK13 expression could not be confirmed in OOCs, being inconsistent with our present result. On the other hand, Koizumi (29) stated that CK13 was partially positive in OOCs, supporting of our result.…”

“…In a comparison between OOCs as representative of developmental cysts and KCOTs as neoplastic cystic lesions, differences in expression were evident among CK10, CK17, and CK19. CK10 (56.5 kDa) is expressed in keratinized stratified squamous epithelium, except for the basal layer (25,27,29). CK10 positivity was evident in the Su and SP of OOCs, indicating they differ from lesions such as KCOTs and DCs.…”

“…In addition, Crivelini et al (30) described that CK13 expression in odontogenic epithelium was consistent with its expression in dental lamina. Furthermore, several reports have indicated that CK13 is positive in lesions derived from odontogenic epithelium, such as radicular cysts, DCs, ameloblastomas and KCOTs (24)(25)(26)(27)(28)(29). CK17 (46 kDa) is expressed in the anlage of sweat glands, hair follicles and teeth (31), and also in lesions such as odontogenic cysts and tumors (24)(25)(26)32).…”

Orthokeratinized Odontogenic Cyst: An Unusual Histopathological Presentation

“…On the other hand, a previous study showed that most OOCs and dermoid cyst specimens express CK10. This finding also suggests that OOCs may originate from the oral epithelial component, whereas KCOTs originate from dental lamina (13). This would explain the occurrence of KCOTs in the posterior mandible, where the dental lamina is more active at the age that patients develop this lesion (1).…”

Cysts and Pseudocysts of the Oral Cavity: Revision of the Literature and a New Proposed Classification

“…They can lead to the formation of an inflammatory radicular-necrotic cyst (RC), that can be periapical or peri-radicular. First event is the formation of a granuloma, that subsequently gives rise to a cyst, whose epithelium expresses a specific odontogenic CK such as 19 in the superficial cell layers (24)(25)(26) and co-expresses CK5 in the cyst lining (18). A peculiar variant of RC is considered the Residual Radicular Cysts that develop from apical granulomas or residual fragments of RC (5,6).…”