Classification of Odontogenic Tumors – Modified WHO classification

Tumors of Odontogenic tumors refer to the lesions which arise from odontogenic remnants or residues such as Odontogenic epithelia, odontogenic mesenchyme. It includes the formation of hard tissue as well similar to tooth development. Apart from arising from odontogenic remnants, there have been cases where the tumors have developed from a preexisting developmental cyst such as a Dentigerous cyst or Adenomatoid Odontogeic Cyst and also from other tumors like Ameloblastoma.

• Adenomatoid Odontogenic Tumor

Odontogenic tumors are both Benign and Malignant and have been classified accordingly by WHO in 1992 which was further divided into sub divisions by White DK in 2004. Benign Odontogenic tumors are divided into three types based on the presence / absense of odontogenic epithelium or ectomesenchyme. While the Malignant Odontogenic tumors are divided into Carcinomas and Sarcomas.

Classification of Odontogenic tumors – Modified WHO

The classification was first given in 1992 which was later modified by White DK in 2004 by including Sub divisions.

Benign Odontogenic Tumors:

1. Odontogenic Epithelium without odontogenic ectomesenchyma: In this case, the tumor is entirely made up of epithelial component without any contribution from extomesenchyme

• Ameloblastoma
• Squamous Odontogenic Tumor
• Calcifying epithelial odontogenic tumor or Pindborg tumor
• Adenomatoid Odontogenic Tumor

2. Odontogenic Epithelium with odontogenic ectomesenchyme with or without hard tissue formation: 

• Ameloblastic Fibroma
• Ameloblastic Fibrodentinoma
• Ameloblastic fibro-odontoma
• Odontoameloblastoma
• Calcifying Odontogenic Cyst
• Complex Odontoma
• Compound Odontoma

3. Odontogenic ectomesenchyme with or without included odontogenic Epithelium

• Odontogenic Fibroma
• Myxoma or Myxofibroma
• Cementoblastoma – Bening or True

Malignant Odontogenic Tumors:

1. Odontogenic Carcinomas:

• Malignant Ameloblastoma
• Primary intraosseous carcinoma
• Clear cell odontogenic carcinoma
• Ghost cell odontogenic carcinoma

2. Odontogenic Sarcomas:

• Ameloblastic fibrosarcoma
• Ameloblastic fibrodentinosarcoma
• Ameloblastic fibro-odontosarcoma

Histology of both benign and malignant odontogenic lesions can be determined by their location or site and structure in which they are located. Radiographic, Clinical and Histologic features need to be taken into account before diagnosis of the lesion, a biopsy or FNAC might also be needed in some cases for Confirmation of the lesion. The proper diagnosis of Odontogenic lesion helps in determining a proper Treatment Plan which consists of Surgical intervention in most cases. The prognosis of the treatment depends on the type of lesion Benign or Carcinogenic and also on the amount of Hard and Soft tissue damage done.