Primary intraosseous squamous cell carcinoma in odontogenic keratocyst: A rare entity

Abstract

Squamous cell carcinoma (SCC) arising from the wall of an odontogenic cyst (also known as primary intraosseous carcinoma) is a rare tumor which occurs only in jaw bones. This tumor was first described by Loos in 1913 as a central epidermoid carcinoma of the jaw. Primary intraosseous carcinomas (PIOC) may theoretically arise from the lining of an odontogenic cyst or de novo from presumed odontogenic cell rests. According to the new histological classification of tumors of the World Health Organization, odontogenic keratocyst is nowadays considered a specific odontogenic tumor and the PIOC derived from it is considered as a specific entity which is different from other PIOCs derived from the odontogenic cysts. The following report describes a case of such extremely rare entity that is primary intraosseous SCC of the mandible derived from an OKC in a 60-year-old male patient with brief review of literature.

Keywords: Mandible; odontogenic cyst; odontogenic keratocyst; primary intraosseous squamous cell carcinoma.

Figure 1

Extraoral swelling involving from the right angle to left angle of mandible

Figure 2

Intra-oral image showing intact overlying alveolar mucosa

Figure 3

Orthopantomogram revealed a multilocular radiolucent lesion extending from the right angle of mandible to left angle of mandible

Figure 4

Photomicrograph of the section shows 8–10 layers thick parakeratinized stratified squamous epithelium with palisaded basal cell layer (H&E stain, x100)

Figure 5

Photomicrograph of proliferating odontogenic epithelium with features of dysplasia (H&E stain, x200)

Figure 6

(a) Proliferated cystic lining with dysplastic islands in the cystic capsule (H&E stain, x40). (b) Dysplastic islands are made up of moderately to poorly differentiated squamous cell (H&E stain, x400)