A neoplasm is abnormal tissue that grows by cellular proliferation more rapidly than normal tissue. Its growth continues even after the stimuli that started the growth have ended. Neoplasms lack structural organization and functional coordination with normal tissue, usually forming a distinct mass. The coding of neoplasms requires a good understanding of anatomy and medical terminology as this article will show. In ICD-9-CM, all neoplasms are classified to Chapter 2 in the Tabular List. The Table of Neoplasms in the Alphabetic Index lists code numbers for neoplasms by anatomical site. Code numbers representing six types of neoplasm behavior are listed for each site.

Neoplasm Behaviors

Malignant neoplasms are composed of tumor cells that can invade surrounding structures or distant organs. Their growth is more rapid than that of benign neoplasms. ICD-9-CM classifies malignant neoplasms as primary, secondary, and carcinoma in situ. Primary identifies the site of origin of the neoplasm. The point of origin is determined through study of the morphology (form and structure) of the tumor cells. Determination of the point of origin and type of cells is important in establishing the severity of illness and planning treatment. Secondary identifies the site(s) to which the primary site has spread by direct extension to surrounding tissues or metastasized by lymphatic spread, invasion of blood vessels, or implantation as tumor cells are shed into body cavities. The morphology of a metastatic neoplasm is the same as that of the primary neoplasm. Carcinoma in situ is composed of tumor cells which are undergoing malignant changes; however, these changes do not extend beyond the point of origin or invade surrounding normal tissue. Carcinoma in-situ is also described as non-infiltrating, non-invasive, or pre-invasive carcinoma.

Benign neoplasms are tumors which do not invade adjacent structures or spread to distant sites. Their growth may displace or exert pressure on adjacent structures. The impingement on surrounding organs can result in local symptoms. Some benign neoplasms have no potential for malignancy. However, others, such as adenomatous gastric polyps, have a pre-malignant potential, and removal is indicated. Fortunately, most benign tumors can be completely excised.

The classification Of Uncertain Behavior includes tumors which show features of both benign and malignant behavior. These tumors may require further study before a definitive diagnosis can be established. The codes in this category should only be assigned when documentation by the pathologist clearly indicates that the behavior of the neoplasm cannot be identified.

If neither the behavior nor histological type of tumor are specified in the diagnostic statement, a neoplasm is classified to be of Unspecified Nature. This type of diagnosis may be encountered when the patient has been treated elsewhere and now presents to a different facility without accompanying information, is referred elsewhere for definitive work-up, or work-up is not performed due to the patient's advanced age or poor condition.

Coding Neoplasms

ICD-9-CM classifies neoplasms by system, organ, or site. Exceptions to this are lymphatic and hematopoietic neoplasms, malignant melanoma of the skin, and some common tumors of bone, uterus, and ovary. Because of these exceptions, the alphabetic index should be checked first to see if there is a specific code assigned to a listed morphological type, such as sarcoma, adenoma, and melanoma. The alphabetic listing also directs coders to the appropriate classification of neoplasms which do not have a code for a specific morphological type. For example, "Osteoma" directs coders to "see Neoplasm, bone, benign." A note at the beginning of the Neoplasm Table instructs coders that guidance in the alphabetic index may be overridden if a descriptor is present. For example, malignant adenoma of the colon is coded to 153.9 rather than 211.3 because the adjective "malignant" overrides the index entry "Adenoma--see also Neoplasm, benign."

If a specific neoplasm diagnosis indicates which column of the Neoplasm Table is appropriate and does not delineate a specific type of tumor, the table may be consulted directly. Some sites on the table are marked with an asterisk (*), such as "extremity*" or "knee, NEC*." These should be classified to malignant neoplasm of the skin of these sites if the type of neoplasm is a squamous cell carcinoma or epidermoid carcinoma and to benign neoplasm of the skin of these sites if the neoplasm is any type of a papilloma.

Primary neoplasms are classified to the site of origin. In the case of malignant neoplasms originating from contiguous sites, it may not be possible to delineate the point of origin. These neoplasms are given the fourth digit assignment of 8. For example, a malignant neoplasm of overlapping sites of the pancreas is coded to 157.8, Malignant neoplasm of contiguous or overlapping sites of pancreas whose point of origin cannot be determined.

ICD-9-CM includes two categories that depart from the usual principles of classification. These codes are 150, Malignant neoplasm of the esophagus, and 201, Hodgkin's disease. In these codes the fourth digit subdivisions are not mutually exclusive. This dual-axis classification allows for variation in terminology used by physicians. For example, different physicians may describe the same neoplasm as being located in the thoracic esophagus (150.1) or the middle third of the esophagus (150.4).

When treatment is directed at the primary site of the malignancy, the primary site is designated as the principal diagnosis. An exception to this is if the hospital admission or encounter is solely for the administration of radiotherapy (V58.0) or chemotherapy (V58.1). In these instances, the V-code is sequenced as the principal diagnosis and the malignancy, either primary or secondary, as a secondary diagnosis. The malignancy should be coded using codes in the 140-198 or 200-203 series for as long as adjunct chemotherapy or radiotherapy is being administered.

If the primary malignancy has been excised or eradicated and the patient is not receiving adjunct treatment to the site and shows no evidence of remaining malignancy, a code from the V10 series, Personal history of malignant neoplasm, is assigned. The fourth and fifth digits specify the site of the primary malignancy. Any extension, invasion, or metastasis to another site is coded as a secondary malignant neoplasm. If treatment of the secondary neoplasm is the reason for admission, it is sequenced as the principal diagnosis.

If a secondary malignancy is not present and the patient is admitted for follow-up, two codes are required. For example, if a patient is admitted for follow-up of carcinoma of the colon following radiotherapy and recurrence is not found, V67.1, Follow-up examination following radiotherapy, is sequenced as the principal diagnosis. V10.05, Personal history of malignant neoplasm of the large intestine, is a secondary diagnosis. Malignancies of the hematopoietic and lymphatic tissue specified as "in remission" are assigned codes from the V10.60-V10.79 series. If the primary malignancy has recurred, it is coded as a primary malignancy of the designated site and sequenced as dictated by the circumstances of admission. V-codes would not be used in this situation.

Because of the ambiguity sometimes seen when a diagnosis of metastatic carcinoma is given, rules have been implemented for clarification. Cancer "metastatic to" a site is interpreted as a secondary neoplasm of that site. For example, metastatic carcinoma to the liver is coded as 197.7, Neoplasm of the liver, specified as secondary. Cancer described as "metastatic from" a site is interpreted as a primary malignancy of that site. A diagnosis of metastasis from the thyroid is coded to 193, Malignant neoplasm of the thyroid gland. Secondary codes are assigned for the metastatic sites.

If the diagnostic statement lists only one site and it is identified as metastatic, it should be coded as a primary neoplasm of unspecified site for the morphological type. If the morphological type is not identified in the medical record, the site qualified as metastatic is coded as a primary malignant neoplasm of the given site unless it is one of the following sites:

• Bone
• Brain
• Diaphragm
• Heart
• Liver
• Lymph nodes
• Mediastinum
• Meninges
• Peritoneum
• Pleura
• Retroperitoneum
• Spinal cord
• Sites classifiable to 195

These sites are coded as secondary neoplasms unless they are otherwise designated. Appropriate codes should also be assigned for the primary or secondary malignant neoplasms of the specified or unspecified sites included in the diagnostic statement. For example, a diagnosis of metastatic carcinoma of the peritoneum is coded to 197.6, Secondary malignant neoplasm of retroperitoneum and peritoneum, and 199.1, Malignant neoplasm without specification of site, other. In this case, the peritoneum is one of the sites listed as an exception, resulting in a code assignment of secondary neoplasm of the peritoneum and primary malignant neoplasm of an unspecified site.

A diagnosis of metastatic carcinoma of the ovary would be coded to 183.0, Malignant neoplasm of ovary, and 199.1, Malignant neoplasm without specification of site, other. Since the site mentioned is not one of the exceptions, it is coded as a primary neoplasm of the stated site, and the secondary neoplasm is coded as an unspecified site.

If two or more sites are documented as metastatic in the diagnostic statement, the stated sites should be coded as secondary neoplasms and the primary site as unknown. In the event the diagnosis does not specify a site, but the morphological type is documented as metastatic, codes should be assigned for a primary neoplasm of unknown site and secondary neoplasm of unspecified site.

Sequencing Neoplasms

If a neoplasm is determined to be the reason for admission, the focus of treatment can be used to select the correct code for the principal diagnosis. If treatment is directed toward the primary neoplasm, it is sequenced as the principal diagnosis. If admission is for treatment directed only at a secondary site, the metastatic site is sequenced as the principal diagnosis and the primary site as a secondary diagnosis.

An exception is the admission for the administration of radiotherapy or chemotherapy. In this event, the principal diagnosis is V58.0 or V58.1 followed by the secondary code(s) for the site(s) of the malignancy. If the patient is admitted for definitive therapy such as surgery, diagnostic procedures, staging, or palliative procedures and receives radiotherapy or chemotherapy during the admission, the malignancy is sequenced as the principal diagnosis, and V-codes are not assigned.

If a patient is admitted with a symptom, sign, or ill-defined condition associated with a malignancy, the malignancy is sequenced as the principal diagnosis. Basic coding guidelines dictate that if a related definitive diagnosis has been established as the cause of the symptom(s), it should be sequenced first.

Frequently, a patient with a malignancy will be admitted with an acute condition such as anemia or dehydration. This may be due to the malignancy itself or the therapy received. If treatment is directed toward the acute condition, it is sequenced as the principal diagnosis and the malignancy as a secondary diagnosis.

In coding neoplasms, three factors must be taken into consideration:

• Behavior of the neoplasm;
• Site of the neoplasm; and
• Reason for admission.

Understanding and following the guidelines outlined in this article then ensures the selection of accurate codes and correct identification and sequencing of principal and secondary diagnoses.

Back to the beginning of Neoplasms