[Revision of the 1992 edition of the WHO histological typing of odontogenic tumors. A suggestion].

The WHO classification of odontogenic tumors (1992, OT) was revised. The following main changes were proposed: (1) OT are not only "related to" odontogenic tissues but are derived from these; (2) the stroma of the epithelial tumor group (1.1.1) is of a fibrous nature and does not contain any ectomesenchymal component; (3) subtypes of ameloblastomas have to be differentiated (intra-, extraosseous, desmoplastic, unicystic); (4) eponyms are no longer used in the revised classification; (5) the AOT is reclassified as an epithelial OT; (6) a neoplastic and non-neoplastic line of the ameloblastic fibroma and ameloblastic fibrodentinoma is proposed; (7) the calcifying ghost cell odontogenic tumor is included in the classification; (8) the simple and the WHO type of odontogenic fibroma are included in the classification; (9) the classification of malignant OT is adapted from Eversole (1999) with a few changes. In particular, ameloblastic carcinoma is differentiated from malignant ( metastasizing) ameloblastoma; (10) the term carcinoma in intraosseous (peripheral) ameloblastoma is introduced. Also, the malignant epithelial odontogenic ghost cell tumor is termed calcifying ghost cell odontogenic carcinoma; (11) the clear cell odontogenic tumor is termed clear cell odontogenic carcinoma; (12) the so-called pseudocysts are termed "cavities" (aneurysmal bone cavity, simple bone cavity, lingual and buccal mandibular bone cavity, focal marrow-containing jaw cavity).