Resumo

NASCIMENTO, Rodrigo Dias et al. Orthokeratinized Odontogenic Cyst x Keratocystic Odontogenic Tumour: The Importance of Differential Histopathogenesis in the Treatment. Rev. cir. traumatol. buco-maxilo-fac. [online]. 2012, vol.12, n.1, pp. 19-26. ISSN 1808-5210.

The orthokeratinized odontogenic cyst (OOC) and keratocystic odontogenic tumour (KCOT) are distinct lesions with similar clinical behavior and radiological features. According to the latest edition of the WHO classification, the KCOT is now classified as an odontogenic neoplasm and the OOC continuesto be classified as an odontogenic cyst. This change made in the classification of KCOT was based on scientific evidence that demonstrated that the proliferation rate of these lesions is not compatible with cystic lesions, a fact demonstrated by the high rate of recurrence found in KCOT. Due to their clinical and radiological similarities, the histological differentiation of these lesions is crucial when choosing whether to adopt a conservative or invasive plan of treatment. In this paper, we describe a 28-year-old male patient, caucasian, with asymptomatic increased volume in the mandible in the region of teeth 33, 34 and 35, all with vitality. The imaging studies revealed a radiolucent lesion in the left mandibular body and parasymphysis. The patient underwent aspiration with negative results and incisional biopsy. The material collected was sent to an anatomic pathology laboratory, and the report revealed a keratocystic odontogenic tumour. The patient therefore underwent a surgical enucleation with marginal curettage, with an unremarkable postoperative course. The material collected during the enucleation was sent to the Oral Pathology Department at the School of Dentistry, São José dos Campos - UNESP, whose report revealed a cystic lesion lined by orthokeratinizing epithelium compatible with an orthokeratinized odontogenic cyst, which was at odds with the result obtained in the incisional biopsy. The patient has been followed up for 72 months with no evidence of recurrence of the lesion.

Palavras-chave : Orthokeratinized Odontogenic Cyst; Keratocystic Odontogenic Tumour; Radiology; Mandible; Bone.