Ameloblastomatous Calcifying Odontogenic Cyst: Case Report ATOUSA AMINZADEH 1 and ALIREZA SADIGHI 2 * 1 Department of oral maxillofacial pathology, school of dentistry, Islamic Azad university Isfahan (khorasgan) branch, Isfahan, Iran. 2 Department of oral maxillofacial surgery, school of dentistry, Islamic Azad university Isfahan (khorasgan) branch, Isfahan, Iran. Abstract Calcifying odontogenic cyst (COC) or calcifying cystic odontogenic tumor was first introduced in 1962 by Gorlin et al., as a possible oral counterpart of calcifying epitheliomas of Malherbe in skin. This lesion is a rare odontogenic lesion with variable clinico-histological characteristics. Three different histologic subtypes has been reported for COC. In this study we presented a female patient diagnosed with ameloblastomatous COC a very rare variant of this lesion and challenges regarding microscopic diagnosis and treatment of it is discussed. Article History Received: 17 April 2019 Accepted: 19 June 2019 Keywords Ameloblastoma; Calcifying Odontogenic Cyst; Jaw Cyst; Odontogenic Cyst. CONTACT Alireza Sadighi Ar.sadighi@khuisf.ac.ir Department of oral maxillofacial surgery, school of dentistry, Islamic Azad university Isfahan(khorasgan) branch, Isfahan, Iran. © 2019 The Author(s). Published by Enviro Research Publishers. This is an Open Access article licensed under a Creative Commons license: Attribution 4.0 International (CC-BY). Doi: http://dx.doi.org/10.12944/CDRJ.01.O1.02 Introduction Calcifying odontogenic cyst (COC) or calcifying cystic odontogenic tumor was first introduced in 1962 by Gorlin et al as a possible oral counterpart of calcifying epitheliomas of Malherbe in skin. COC is a rare odontogenic lesion with variable clinico-histological characteristics. According to literature only 2% of all odontogenic lesions are COC. Mostly COCs grow as cysts; however in less than 5% COCs can occur as a solid tumor-like mass. 1, 2 The basic histopathologic criteria introduced for microscopic diagnosis of cystic COC is an odontogenic ameloblastoma-like epithelium containing numerous ghost cells and calcification. 1 But in regard to some microscopic details observed in a few cystic COCs three different histologic subtypes has been considered for cystic COC : simple unicystic type, odontoma producing type and ameloblastomatous proliferating type. 3 65% of cases are simple cystic which is composed of Current Dental Research Journal dentaljournal.org Vol. 01, No. (1) 2019, Pg. 08-13