International Classification of Diseases for Oncology (3 Rev ed)

The third edition of the tool for coding diagnoses of neoplasms in tunour and cancer registrars and in pathology laboratories.

ICD-O is a dual classification with coding systems for both topography and morphology.

The topography code describes the site of origin of the neoplasm and uses the same 3-character and 4-character categoriess as in the neoplasm section of "Chapter 11, ICD-10".

The morphology code describes the characteristics of the tumour itself, including its cell type and biological activity.

The alphabetical index gives codes for both topography and morphology and includes selected tumour-like lesions and conditions.

A guide to differences in morphology codes between the second and third editions is provided in the final section, which includes lists of all new code numbers, new terms and synonyms added to existing code definitions, terms that changed morphology codes, terms for conditions now considered malignant, deleted terms, and terms that changed behaviour codes.