Chapter II


This chapter contains the following broad groups of neoplasms:
C00-C97 Malignant neoplasms
C00-C75 Malignant neoplasms, stated or presumed to be primary, of specified sites, except of lymphoid, haematopoietic and related tissue
C00-C14 Lip, oral cavity and pharynx
C15-C26 Digestive organs
C30-C39 Respiratory and intrathoracic organs
C40-C41 Bone and articular cartilage
C43-C44 Skin
C45-C49 Mesothelial and soft tissue
C50 Breast
C51-C58 Female genital organs
C60-C63 Male genital organs
C64-C68 Urinary tract
C69-C72 Eye, brain and other parts of central nervous system
C73-C75 Thyroid and other endocrine glands
C76-C80 Malignant neoplasms of ill-defined, secondary and unspecified sites
C81-C96 Malignant neoplasms, stated or presumed to be primary, of lymphoid, haematopoietic and related tissue
C97 Malignant neoplasms of independent (primary) multiple sites
D00-D09 In situ neoplasms
D10-D36 Benign neoplasms
D37-D48 Neoplasms of uncertain or unknown behaviour [see note before D37]


1. Primary, ill-defined, secondary and unspecified sites of malignant neoplasms

Categories C76-C80 include malignant neoplasms for which there is no clear indication of the original site of the cancer or the cancer is stated to be "disseminated", "scattered" or "spread" without mention of the primary site. In both cases the primary site is considered to be unknown.

2. Functional activity

All neoplasms are classified in this chapter, whether they are functionally active or not. An additional code from Chapter IV may be used, if desired, to identify functional activity associated with any neoplasm. For example, catecholamine-producing malignant phaeochromocytoma of adrenal gland should be coded to C74 with additional code E27.5; basophil adenoma of pituitary gland with Cushing's syndrome should be coded to D35.2 with additional code E24.0.

3. Morphology

There are a number of major morphological (histological) groups ofmalignant neoplasms: carcinomas including squamous (cell) and adeno-carcinomas; sarcomas; other soft tissue tumours including mesotheliomas; lymphomas (Hodgkin's and non-Hodgkin's); leukaemia; other specified and site-specific types; and unspecified cancers. Cancer is a generic term and may be used for any of the above groups, although it is rarely applied to the malignant neoplasms of lymphatic, haematopoietic and related tissue. "Carcinoma" is sometimes used incorrectly as a synonym for "cancer".

In Chapter II neoplasms are classified predominantly by site within broad groupings for behaviour. In a few exceptional cases morphology is indicated in the category and subcategory titles.

For those wishing to identify the histological type of neoplasm, comprehensive separate morphology codes are provided ( see section Morphology of neoplasms). These morphology codes are derived from the second edition of International Classification of Diseases for Oncology (ICD-O), which is a dual-axis classification providing independent coding systems for topography and morphology. Morphology codes have six digits: the first four digits identify the histological type; the fifth digit is the behaviour code (malignant primary, malignant secondary (metastatic), in situ, benign, uncertain whether malignant or benign); and the sixth digit is a grading code (differentiation) for solid tumours, and is also used as a special code for lymphomas and leukaemias.

4. Use of subcategories in Chapter II

Attention is drawn to the special use of subcategory .8 in this chapter [see note 5]. Where it has been necessary to provide subcategories for "other", these have generally been designated as subcategory .7.

5. Malignant neoplasms overlapping site boundaries and the use of sub- category .8 (overlapping lesion)

Categories C00-C75 classify primary malignant neoplasms according to their point of origin. Many three-character categories are further divided into named parts or subcategories of the organ in question. A neoplasm that overlaps two or more contiguous sites within a three-character category and whose point of origin cannot be determined should be classified to the subcategory .8 ("overlapping lesion"), unless the combination is specifically indexed elsewhere. For example, carcinoma of oesophagus and stomach is specifically indexed to C16.0 (cardia), while carcinoma of the tip and ventral surface of the tongue should be assigned to C02.8. On the other hand, carcinoma of the tip of the tongue extending to involve the ventral surface should be coded to C02.1 as the point of origin, the tip, is known. "Over-lapping" implies that the sites involved are contiguous (next to each other). Numerically consecutive subcategories are frequently anatomically contiguous, but this is not invariably so (e.g. bladder C67.-) and the coder may need to consult anatomical texts to determine the topographical relationships.

Sometimes a neoplasm overlaps the boundaries of three-character categories within certain systems. To take care of this the following subcategories have been designated:

   C02.8   Overlapping lesion of tongue
   C08.8   Overlapping lesion of major salivary glands
   C14.8   Overlapping lesion of lip, oral cavity and pharynx
   C21.8   Overlapping lesion of rectum, anus and anal canal
   C24.8   Overlapping lesion of biliary tract
   C26.8   Overlapping lesion of digestive system
   C39.8   Overlapping lesion of respiratory and intrathoracic organs
   C41.8   Overlapping lesion of bone and articular cartilage
   C49.8   Overlapping lesion of connective and soft tissue
   C57.8   Overlapping lesion of female genital organs
   C63.8   Overlapping lesion of male genital organs
   C68.8   Overlapping lesion of urinary organs
   C72.8   Overlapping lesion of central nervous system

An example of this is a carcinoma of the stomach and small intestine, which should be coded to C26.8 (Overlapping lesion of digestive system).

6. Malignant neoplasms of ectopic tissue

Malignant neoplasms of ectopic tissue are to be coded to the site mentioned, e.g. ectopic pancreatic malignant neoplasms are coded to pancreas, unspecified (C25.9).

7. Use of the Alphabetical Index in coding neoplasms

In addition to site, morphology and behaviour must also be taken into consideration when coding neoplasms, and reference should always be made first to the Alphabetical Index entry for the morphological description.

The introductory pages of Volume 3 include general instructions about the correct use of the Alphabetical Index. The specific instructions and examples pertaining to neoplasms should be consulted to ensure correct use of the categories and subcategories in Chapter II.

8. Use of the second edition of International Classification of Diseases for Oncology (ICD-O)

For certain morphological types, Chapter II provides a rather restricted topographical classification, or none at all. The topography codes of ICD-O use for all neoplasms essentially the same three- and four-character categories that Chapter II uses for malignant neoplasms (C00-C77, C80), thus providing increased specificity of site for other neoplasms (malignant secondary (metastatic), benign, in situ and uncertain or unknown).

It is therefore recommended that agencies interested in identifying both the site and morphology of tumours, e.g. cancer registries, cancer hospitals, pathology departments and other agencies specializing in cancer, use ICD-O.