International Harmonization of Rat Nomenclature

Final Version
Spring 2000

The international harmonized nomenclature which is presented on this Web site is the result of discussions among the Rat Nomenclature Reconciliation Subcommittee, a presentation during the 1999 Annual STP Meeting in Washington, D.C., and comments which have been sent to the committee up to December 1999. The drafts were based on the STP, WHO/IARC/RITA and NACAD nomenclature systems and were present for discussion in the Internet since Spring 1999.

Please use the functions of the bottom navigation bar to explore the terminology.


The goal of scientists working in the field of toxicologic pathology is since many years the harmonization of nomenclature and diagnostic criteria for lesions observed in laboratory rats and mice. Initiatives had been started in the late 80s in the United States by the STP (Society of Toxicologic Pathologists) and in Europe by the RITA data base group (Registry of Industrial Toxicology Animal-data), which both lead to internationally recognized publications ("SSNDC: Guides for Toxicologic Pathology", "WHO/IARC: International Classification of Rodent Tumours").

In 1994 the "Joint STPs/ILSI Committee on International Harmonization of Nomenclature and Diagnostic Criteria in Toxicologic Pathology" was established with the objective to coordinate the international activities for the standardization of diagnostic criteria of proliferate lesions in mice and to reconciliate the already published nomenclature of proliferative lesions in rats. Consequently, the "Rat Nomenclature Reconciliation Subcommittee" was formed during the 1998 Annual STP meeting in Vancouver with the goal to eliminate discrepancies existing between the published nomenclature systems and to reach a common consensus. The result of the work is now available here, showing in a tabular format the recommended nomenclature and the terminology established by STP, WHO/IARC/RITA, and NACAD.

Currently the diagnostic criteria published by STP and WHO/IARC are checked for consistency with the goal to identify major discrepancies.

For more details and explanations please use the following links:

Remarks on updates: Web sites usually are updated frequently and users look for such updates as a "feature" in order to get current information. However, this is not the case with this Web site: a standardized nomenclature, once established and agreed upon by a large number of experts, should be kept constant to fulfill the goal!

Last Update: 22-Jun-2000
This Web Site has been created and is maintained by the Departments of Information Technology / Pathology of the Fraunhofer Institute of Toxicology and Aerosol Research, Hannover, Germany