Orthokeratinized odontogenic cyst with calcification: A rare case report of a distinct entity

Abstract

Orthokeratinized odontogenic cyst (OOC) is a relatively rare odontogenic cyst, distinct from odontogenic keratocyst (OKC). In the 4th edition of WHO Classification of Head and Neck Tumors (2017), OOC has been included as a separate entity in the category of developmental odontogenic cysts. It presents as a unilocular radiolucent lesion in the posterior mandible and is frequently related to impacted teeth, thus mimicking dentigerous cyst. Due to low local aggressiveness and no association with nevoid basal cell carcinoma syndrome, it does not show tendency to recur. When compared to OKC, OOC exhibits substantial number of differences with respect to clinical, pathological and behavioral features and treatment modalities. Hence, recognizing OOC as unique lesion is mandatory to avoid unnecessary overtreatment. This paper aims to report a rare case of OOC associated with impacted tooth, showing calcifications and emphasizes its differences from OKC. Furthermore, the recent concepts about OKC and OOC are discussed.

A Rare Case of Orthokeratinized Odontogenic Cyst (OOC) in the Posterior Mandible of a Young Adult 18-Year-Old Boy

“…OOC (orthokeratinized odontogenic cyst) originates from the cellular remains of the dental lamina, and is one of the developmental cysts of the jaw with a low incidence 3 , 9 - 11 .…”

“…Orthokeratinized Odontogenic Cyst (OOC) is a rare developmental odontogenic cyst 3 , 9 - 11 , arising from the remnants of the dental lamina 3 , 5 , 9 - 13 . Schultz in 1927 first recognized OOC as a dermoid cyst 10 , 12 .…”

“…Among its histopathological features, one of the things that plays a role in differentiating it from other lesions such as OKC whose covering is parakeratinized, is its orthokeratinized epithelial covering 5 , 9 - 11 .…”

“…Although high recurrence is a common feature of OKC 1 , 2 , 4 - 6 , 8 , 10 - 12 ; the recurrence rate of OOC is low 5 , 9 - 13 and there is no need for invasive methods for treatment, and OOC can be treated with conservative methods, resulting in fewer and undesirable complications for the patient 11 .…”

“…Also, like OKC, it is often has been reported in the lower jaw 9 , 10 , 12 . In terms of gender predominance, it is often reported in men 3 , 9 - 11 . The occurrence of OOC was observed more in the 3rd and 4th decades of life 10 , 11 , on the contrary, the case reported in this article was 18 years old.…”