Gastroenterology Coding Alert

Polyp Diagnosis Coding:

Specify Location to Pinpoint the Right Colon Polyp Diagnosis Codes

Published on Tue Jul 20, 2021

Don’t be vague when seeking polyp location.

When selecting a diagnosis code for a polyp removal, you should answer these three basic questions:

1. What was the polyp’s specific location? For polyps in the colon, documentation should indicate the specific colon site.

It’s not enough to just write “polyp in the rectal area” or “polyp higher in the colon.” ICD-10 codes are very location-specific, and even for the colon region, there are six polyp codes (D12.0 to D12.5) based upon whether the polyp is in the cecum, appendix, ascending colon, transverse colon, the descending colon, or the sigmoid colon. You should use the non-specific polyp code D12.6 (Benign neoplasm of colon, unspecified) only as a last resort.

For the rectal region also, the codes include D12.7 (Benign neoplasm of rectosigmoid junction), D12.8 (Benign neoplasm of rectum), and D12.9 (Benign neoplasm of anus and anal canal).

2. Was this really a polyp removal or something else? Gastroenterologists use the snare removal technique to completely remove an abnormal growth or to partially remove a piece of a larger mass for pathologic identification. Look for the key words within the procedure description, including “polyp,” “lipoma,” or “mass.”

3. What if the neoplasm’s exact site is untraceable? In cases of colon cancer, sometimes your physician may find it difficult to pinpoint the cancer’s primary site because the cancer has already metastasized to neighboring tissue. In such cases, you can report the appropriate malignant neoplasm code, such as C18.8 (Malignant neoplasm of overlapping sites of colon) or C18.9 (Malignant neoplasm of colon, unspecified).

Check Path Report to Determine Correct Colonic-Polyp Type

The physician will demarcate a polyp either as non-neoplastic or neoplastic, but only after the final pathology report comes back. This finding determines the proper time interval for a follow-up colonoscopy.

If you are looking at the pathology report to determine a diagnosis code, you may encounter several different types of non-neoplastic colonic polyps that include:

Hyperplastic: Although they are not neoplasms per se, hyperplastic polyps in the colon most often occur in the rectal region, and you should report them with codes in D12.7-D12.9 range. Hyperplastic polyps noted in any other region are reported with codes D12.0-D12.5.

Mucosal: These are usually benign, and you should also report them with colonic codes D12.0-D12.5.

Inflammatory or pseudopolyps: These often occur in patients with inflammatory bowel disease or ulcerative colitis. In this case, you should report inflammatory codes from the family K51.4 (Inflammatory polyps of colon) to report these polyps instead of a code from the neoplasm table. Based on the presence or absence of further complications noted by the physician, the code further expands to K51.40 (Inflammatory polyps of colon without complications) or K51.41- (Inflammatory polyps of colon with complications). For example, if the GI notes that the pseudopolyp has an abscess, then you will have to report K51.414 (Inflammatory polyps of colon with abscess).

Hamartomatous (also called Peutz-Jeghers polyps or a juvenile polyp): Again, in this case, rather than a code from the neoplasms table, you should report either code Q85.8 (Other phakomatoses, not elsewhere classified) or Q85.9 (Phakomatosis, unspecified).

You may also find mention of neoplastic polyps in the path report or the physician notes. Types of neoplastic polyps can be:

Adenomatous polyps (APs): Most colorectal cancers arise from this polyp type, and the cancer largely can be prevented by the detection and removal of adenomatous polyps. However, 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 (Z86.010, Personal history of colonic polyps).

If the path report declares a diagnosis of AP of the colon, then the polyp is benign, and will be coded from the D12.- code range. Don’t get confused if you find terms such as tubular adenoma (a benign polyp), villous adenoma of the colon (a carpet-like polyp that can have an uncertain behavior, coded as D37.4, Neoplasm of uncertain behavior of colon), or tubulovillous adenoma (a combination of the tubular and villous adenomas, coded either with D12.- or D37.4). These are the three subcategories of adenomatous polyps. The path report may identify them specifically instead of calling them “adenoma.”

Sessile serrated lesions: Increasingly, endoscopists can identify subtle, nearly flat lesions with histology referred to variably as “sessile serrated polyp (SSP),” “sessile serrated adenoma (SSA),” or “sessile serrated lesion” without any further details. These should be reported as you would an adenomatous polyp (D12.- or D37.4). A patient may also have multiple polyps of different morphologies, such as hyperplastic polyps and APs. In such cases of different diagnoses, you can report one code for each type of polyp.

Adenocarcinomas: When an adenomatous polyp becomes cancerous, it is called an adenocarcinoma and is malignant. Sometimes a neoplastic polyp will contain an area of adenocarcinoma. In these reports the designation may be “high grade dysplasia,” “carcinoma in situ,” or “early invasive carcinoma.”

Familial polyposis (also known as adenomatous polyposis coli): This is a genetic condition in which the patient has dozens (or even hundreds) of adenomatous polyps in the colon. While these polyps are benign, because of their large number and early age of onset, this condition commonly leads to colon cancer, and, when any of these polyps turn malignant, the condition is generally referred to as adenocarcinoma in adenomatous polyposis coli. For this condition, you should add code Z83.71 (Family history of colonic polyps). If the patient indeed has polyposis syndrome, then as above for adenomatous polyps, your diagnosis code is D12.-.

Carcinoids: These relatively rare neuroendocrine tumors are generally referred to as benign or malignant carcinoid tumors. You should code this condition as D3A.029 (Benign carcinoid tumor of the large intestine, unspecified portion).

For Other Neoplasms, Keep These Types in Mind

Pathology reports may also mention submucosal polyps identified variously as lymphoid aggregates, lipomas, leiomyomas, pneumatosis cystoid intestinalis, hemangiomas, fibromas, and metastatic lesions. These can be neoplastic or non-neoplastic, and can appear to be typical colon polyps or neoplasms at the time of the procedure and lesion removal. Lipoma can be diagnosed endoscopically because of its yellow color and softness (pillow sign).

The GI physician may employ ultrasound (EUS, 45391, Colonoscopy, flexible; with endoscopic ultrasound examination limited to the rectum, sigmoid, descending, transverse, or ascending colon and cecum, and adjacent structures) support to define the site of origin and for biopsy of submucosal lesions if the diagnosis is in doubt (45392, Colonoscopy, flexible; with transendoscopic ultrasound guided intramural or transmural fine needle aspiration/ biopsy(s), includes endoscopic ultrasound examination limited to the rectum, sigmoid, descending, transverse, or ascending colon and cecum, and adjacent structures). They rarely become malignant. You should report them with codes from D12.-.

Heads up: The pathology report is also important because it may also provide information on whether the polyp is primary, secondary, or in situ in case of malignancy. For reporting malignant polyps, you should apply the code that refers to a specific location within the colon from the diagnosis code range C18.- (Malignant neoplasm of colon), with a code for cancer in overlapping regions (C18.8), or with a code for an unspecified location (C18.9). You can also choose from C19 (Malignant neoplasm of rectosigmoid junction) or C20 (Malignant neoplasm of rectum) for the rectal region malignancies.

Example: A gastroenterologist performs screening colonoscopy for a Medicare patient due to family history of colon cancer. The patient has no signs and symptoms and also does not have a personal history of any gastrointestinal problems. During the colonoscopy, the gastroenterologist finds a polyp in the ascending colon. They then remove it using snare technique.

Since the gastroenterologist found a polyp during the screening, you cannot report G0105 (Colorectal cancer screening; colonoscopy on individual at high risk) or G0121 (Colorectal cancer screening; colonoscopy on individual not meeting criteria for high risk). Instead, you should report the therapeutic procedural code describing the procedure that your gastroenterologist performed to eliminate the polyp that was found.

Because your gastroenterologist removed the polyp using the snare technique, you will have to report 45385 (Colonoscopy, flexible; with removal of tumor(s), polyp(s), or other lesion(s) by snare technique) instead of the screening HCPCS code. You should also add the PT modifier (Colorectal cancer screening test; converted to diagnostic test or other procedure) to the CPT^® code to tell the CMS contractor that this was a “screening” exam turned therapeutic. You will have to use the Z code Z12.11 (Encounter for screening for malignant neoplasm of colon) if this was the patient’s initial screening examination, and Z80.0 (Family history of malignant neoplasm of digestive organs) to support the medical necessity of conducting the colorectal cancer screening for the patient. The ICD-10 code for the removed colon polyp is D12.2 (Benign neoplasm of ascending colon).

Remember that if the procedure is billed before the pathologic diagnosis is back from the lab, colon polyps that appear benign are coded with K63.5 (Polyp of colon) in nearly all the circumstances above. If a final pathologic diagnosis is back before billing, then the more specific code is reported.