Certain infectious and parasitic diseases

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
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