Where such descriptors are not present, the remainder of the Index should be consulted, where guidance is given to the approriate columns for each morphological (histological) variety listed, e.g. Mesonephroma - see Neoplasm, malignant, Embryoma - see also Neoplasm, uncertain behavior, Bowen's disease - see Neoplasm, skin, in situ. However, the guidance in the Index can be overridden if one of the descriptors mentioned above is present, e.g. malignant adenoma of colon is coded to C18.9 and not to D12.6, as the adjective "malignant" overrides the Index entry "Adenoma - see also Neoplasm, benign".

2. Sites marked with the sign # (e.g. face NEC #) should be classified to malignant neoplasm of skin of these sites if the variety of neoplasm is a squamous cell carcinoma or an e pidermoid carcinoma and to benign neoplasm of skin of these sites if the variety of neoplasm is a papilloma (any type).

3. Carcinomas and adenocarcinomas, of any type other than intraosseous or odontogenic, of sites marked with the sign ◊ (e.g. ischium ◊) should be considered as metastatic from an unspecified primary site and coded to C79.5.

fibrosarcoma, pancreas C25.9

leiomyosarcoma, stomach C16.9

Morphological types that indicate connective tissue appear in their proper place in the alphabetical index with the instruction " see Neoplasm, connective tissue, . . .".