Choose Diagnosis for Colonic Polyps Based on Key Terms

To select the correct ICD-9 diagnosis code for a colonic polyp, gastroenterology coders need to know whether the polyp is benign or malignant. Often, however, the pathology report (PR) will not use either term. Instead a pathological description will be used that points to the usual behavior of the polyp, and coders need to be able to translate those descriptions into benign and malignant.

The PR contains the definitive determination of a colonic polyp’s behavior. To get the true picture of a polyp” you have to wait for the pathology report to come back ” says Roberta Classen CPC CPC-H MCS-P financial manager Charleston (S.C.) Gastroenterology Specialists and a member of the AAPC national advisory board. “Gastroenterologists may imply what type of polyp it is in an operative report but they usually defer to the pathology report before making a recommendation.”

Neoplasm Table Requires Information

Colonic polyps are growths of tissue that protrude from the bowel wall into the lumen. Some are neoplastic (from neoplasm) which means abnormal growth has occurred and there is potential for malignancy. Some are non-neoplastic which means that the growth consists of normal tissue with little or no potential for malignancy.

Coders should consult the neoplasm table in the ICD-9 Alphabetic Index to Diseases (Volume 2) when selecting a diagnosis code for a polyp. All diagnosis codes for neoplastic polyps will come from this table. Some of the diagnosis codes for non-neoplastic polyps will also come from this table. The neoplasms table requires the coder to have three pieces of information about the polyp to choose the correct code:

1. The part of the body. For malignant primary neoplastic polyps in the colon the specific site of the colon (traverse sigmoid ascending descending etc.) must be indicated. For all other behaviors the code descriptions make a general reference to the colon large intestine or digestive system.

2. The behavior of the polyp or its capacity to spread. Benign (noncancerous ) and malignant (cancerous) are two types of behavior. In addition a colonic polyp could be classified as uncertain (235.2) which means that it can’t be determined if the polyp is malignant and the behavior is unpredictable and needs further investigation. It could also be unspecified (239.0) which means that the exact nature of the polyp must be determined by lab tests.

3. Whether the malignancy is primary secondary or in situ. A primary malignant colonic polyp (153.0-154.0) is one where the colon is the original site of the cancer. A secondary malignant colonic polyp (197.5) is one where the cancer has metastasized from another site to the colon. An in situ malignant colonic polyp (230.3-230.4) is one where the cancer is confined to the colon.

It is sometimes difficult to determine the primary site of a cancer because it has already spread to neighboring tissue. Code 153.8 can be used for a “malignant neoplasm of contiguous or overlapping sites of colon whose point of origin cannot be determined ” the ICD-9 manual states.

Morphologies of Non-Neoplastic Polyps

PRs often use a phrase that describes the morphology or form of the polyp such as adenomatous or hyperplastic. Because most morphologies are associated with a specific behavior the coder only has to understand the relationship between a particular morphology and its usual behavior to determine benign or malignant.

Although non-neoplastic polyps do not usually turn cancerous they may cause gastrointestinal problems such as bleeding and obstruction. Morphological descriptions of non-neoplastic polyps found in gastroenterology are:

  • Hyperplastic These polyps are frequently found in the colon and are believed to have no cancerous potential. Although they are not neoplasms hyperplastic polyps in the colon are usually reported with 211.3.
  • Mucosal These are usually benign and should also be reported with 211.3 when found in the colon.
  • Inflammatory or pseudopolyps These are found in patients with inflammatory bowel disease or ulcerative colitis. Use 556.4 (Pseudopolyposis of colon) to report these polyps instead of a code from the neoplasm table.
  • Hamartomatous Also called Peutz-Jeghers polyps they should be reported with 759.6 (Other and unspecified congenital anomalies; other hamartoses not elsewhere classified) rather than a code from the neoplasms table.

    Morphologies of Neoplastic Polyps

    The following morphological terms are often used in PRs to describe neoplastic polyps in the colon:

  • Adenomatous polyps (APs) Gastroenterologists believe that most colorectal cancers arise from this type of polyp but not all adenomas develop into cancer. Because of the potential for malignancy most insurers will reimburse follow-up and surveillance procedures for patients who have adenomatous polyps. Patients with APs are usually designated as having a history of colonic polyps (V12.72) according to Rosario Ligresti MD director of endoscopic ultrasound at New York Medical College in Valhalla.

    When the pathological finding is referred to as an AP of the colon the behavior is benign and the diagnosis code will be 211.3. Instead of calling it an adenoma the PR may also use one of the three subcategories of adenomatous polyps to describe it. A tubular adenoma is a benign polyp. A villous adenoma of the colon is a carpet-like polyp that is usually uncertain (235.2). A tubulovillous adenoma is a combination of the tubular adenoma and villous adenoma and is usually benign.

    Occasionally a polyp will be a combination of hyperplastic and adenomatous. Sometimes referred to as a serrated adenoma this mixed polyp should be treated as if it were adenomatous. It’s also common for patients to have multiple polyps of different morphologies such as pseudopolyps and APs. If the polyps have different diagnoses one for each type of polyp should be reported.

  • Adenocarcinomas When an adenomatous polyp becomes cancerous it is called an adenocarcinoma and is malignant. Two histological subcategories of adenocarcinoma in gastroenterology are tubular adenocarcinoma and villous adenocarcinoma which are also malignant.
  • Familial polyposis Also known as adenomatous polyposis coli this is a genetic condition where the patient has over a hundred adenomatous polyps in the colon. Familial polyposis is benign. It is almost certain however that colon cancer will develop from this condition and when it has turned malignant it is generally referred to as adenocarcinoma in adenomatous polyposis coli.
  • Gastrinomas These are relatively rare neuroendocrine tumors and are generally referred to as a gastrinoma (benign) and a malignant gastrinoma.

The following polyps are neoplasms often found in the colon that rarely become malignant and should be reported with 211.3: lipomas osteomas and leiomyomas.

If the polyp is malignant the PR will also provide information on whether it is primary secondary or in situ. “The gastroenterologist won’t be able to tell you if it’s primary secondary or in situ ” says Sherry Straub manager of coding at Esse Health a multispecialty practice in St. Louis. “You have to look to the pathology report.”

If the pathological description is simply “adenocarcinoma ” the malignancy is primary. “Adenocarcinoma metastatic” indicates that the cancer has metastasized and that this is a secondary site. If the malignancy is in situ that phrase should be part of the pathological description.

Some PRs use “metastatic from” and “metastatic to.” If the carcinoma is described as “metastatic from” a site it is considered to be the primary site. If the description is “metastatic to” a site it is considered a secondary site. In the description “metastatic carcinoma of the colon to the lungs” for example the colon should be coded as the primary site and the lungs would be the secondary site.

Once the diagnosis code has been found in the neoplasm table verify it in the Tabular List (Volume 1) of the ICD-9 manual. Straub says “Sometimes you’ll go there and find that code is really not what you wanted.”

The code descriptions in the tabular list help identify which sites of the colon are covered by a code. A benign polyp in the rectosigmoid junction for example should be reported not as a benign polyp of the colon but as a benign polyp of the rectum (211.4) even though the rectosigmoid junction is often lumped together with the colon in other ICD-9 descriptions.

Benign If No Pathology Report

When it is necessary to file the medical claim before the PR arrives colonic polyps should be reported as 211.3. “A polyp is considered benign until the PR indicates otherwise ” Classen explains. “You don’t want to incorrectly label a patient with cancer. The patient’s future insurance coverage could be jeopardized by an incorrect cancer diagnosis.”

Coders should also not rely on the gastroenterologist’s description of the polyp in the operative report when selecting the diagnosis code. “No mention of ‘benign’ or ‘malignant’ should be in the endoscopic report since at the time of the endoscopy we are never 100 percent sure without the pathologist ” Ligresti says. “If a gastroenterologist sees a large fungating ulcerated mass in the colon he shouldn’t say it’s colon cancer because it doesn’t always have to be. Ischemic colitis can often mimic colon cancer.”