V.3 ICD-O Morphology - Histology, Behavior, and Differentiation

The morphology code indicates the type of cell that has become neoplastic (histology), its biologic activity (behavior), and the tumor grade or differentiation.

CCR NOTE: 2015 ICD-O-3 histology coding changes: There are histology coding changes being implemented for 2015. Many of the new codes cannot be used for 2015 diagnoses because they are not included among the acceptable histologies for the Collaborative Stage algorithms. For the New ICD-O-3 Histology Code Crosswalk for 2015, please see Volume I - Attachment A.

Definitions:

The morphology code consists of three parts:

The histology code (first four digits)
The behavior cord (the fifth digit)
And the grade of differentiation code (the sixth digit)

Histology code identifies the specific cell type of the tumor. Specific cell lines come from different tissues and are extremely important information for the diagnosis and treatment of the disease. For cases or tumors diagnosed after January 1, 2007, also refer to the 2007 Multiple Primary and Histology Coding Rules Manual to determine histology.

Examples:

Adenocarcinoma: is typically a cancer that begins in glandular (secretory) cells. Glandular cells are found in tissue that lines certain internal organs and makes and releases substances in the body, such as mucus, digestive juices, or other fluids. Most cancers of the breast, pancreas, lung, prostate, and colon are adenocarcinomas.
Squamous cell carcinoma: Cancer that begins in squamous cells. Squamous cells are thin, flat cells that look like fish scales, and are found in the tissue that forms the surface of the skin, the lining of the hollow organs of the body, and the lining of the respiratory and digestive tracts. Most cancers of the anus, cervix, head and neck, and vagina are squamous cell carcinomas. Also called epidermoid carcinoma.
Melanoma: A form of cancer that begins in melanocytes (cells that make the pigment melanin). It may begin in a mole (skin melanoma), but can also begin in other pigmented tissues, such as in the eye or in the intestines.
Sources for Determining Histology:

For solid tumors diagnosed January 1, 2007 forward, also refer to the 2007 Multiple Primary and Histology Coding Rules Manual to determine histology.
For hematopoietic and lymphoid cases diagnosed January 1, 2010 and forward, please refer to the 2010 Hematopoietic and Lymphoid Neoplasm Case Reportability and Coding Manual and the Hematopoietic Database.

For historic coding instructions, please click here.

Historic V.3.3.1 Sources for Determining Histology

For hematopoietic and lymphoid cases diagnosed January 1, 2010 and forward, or following installation of CSv2 software, please refer to the 2010 Hematopoietic and Lymphoid Neoplasm Case Reportability and Coding Manual and the Hematopoietic Database.

For cases diagnosed January 1, 2007 through December 31, 2014

For cases or tumors diagnosed after January 1, 2007, refer to the 2007 Multiple Primary and Histology Coding Rules Manual to determine histology.

Prior to January 1, 2007

For cases or tumors diagnosed prior to January 1, 2007, apply the following guidelines:

In coding histology, use all pathology reports regarding the tumor. The specimen taken from a resection is usually the most representative, unless all the cancerous material was removed during a biopsy.

An AJCC staging form may also be used if it is signed by a physician.

Other diagnostic procedures or the final clinical diagnosis may be used as the basis for coding histology only if no pathology report is available.

Document on the abstract, in a text field, every source of information used.

Behavior code indicates whether a tumor is malignant or benign, or uncertain whether benign or malignant.

Grade, or differentiation, indicates the degree of differentiation of the neoplastic cells have from one another. The grade is an indicator of the aggressiveness of the tumor.

Coding Instructions:

The CCR has adopted the ICD-O-3 (International Classification of Diseases for Oncology, Third Edition) as its official morphology code system for all cases diagnosed January 1, 2001 forward.

Note: Although ICD-O-3 is referenced in coding site and histology throughout this document, unless otherwise noted, these statements also apply to ICD-O-2 coding.

Enter the appropriate morphology code