Peripheral adenomatoid odontogenic tumour.

The Adenomatoid Odontogenic Tumour (AOT) is more than 100 years old, known by different names and the term AOT was coined in 1969 by Philipsen and Birn. AOT frequently occurs in intra-osseous location in gnathic skeleton and rarely seen in peripheral forms. These are rare odontogenic tumours, accounting for 2.2--7.1% of all odontogenic tumours, whereas the central or intraosseous variant of AOT in follicular and extra-follicular presentation, accounts for 95.6% of all AOTs. The peripheral variant presents as a gingival mass, which may cause slight saucerization of alveolar bone or might not affect the bone at all. These peripheral variants constitute 4.4% or less, of all AOTs of the gnathic skeleton. Here, we present a rare case of a peripheral variant of AOT in a 35-years-old female, 1.5 to 2 cm in dimension seen on the labial gingiva in right canine-premolar area. The lesion showed marked bone loss in 13 and 14 teeth region, causing mobility of 13. Histopathology showed a well encapsulated tumour mass with metaplastic bone in the capsule. A conventional AOT with ductal and rosette pattern was seen with tumour droplets and amyloid like material. The case clinically presented a moderately aggressive behaviour.