TL;DR: Aetna modified CPB 0747 covering transanal endoscopic microsurgery (TEM), effective November 27, 2025. Billing teams need to confirm ICD-10 diagnosis alignment with the three covered indications before submitting claims under CPT 0184T.
Aetna's TEM coverage policy draws a sharp line. CPT 0184T — excision of rectal tumor via transanal endoscopic microsurgical approach — is covered for exactly three indications and considered experimental for 18 others. If your colorectal surgery or gastroenterology practice bills 0184T for Aetna members, this update to CPB 0747 reflects a modification to Aetna's coverage policy for TEM. Review the criteria below and confirm your claims align with the three covered indications. The gap between "covered" and "not covered" here is wide, and the ICD-10 code you attach to that claim will determine whether you get paid or denied.
Quick-Reference Table
| Field | Detail |
|---|---|
| Payer | Aetna |
| Policy | Transanal Endoscopic Microsurgery — CPB 0747 |
| Policy Code | CPB 0747 |
| Change Type | Modified |
| Effective Date | November 27, 2025 |
| Impact Level | High |
| Specialties Affected | Colorectal Surgery, General Surgery, Gastroenterology |
| Key Action | Audit all 0184T claims against the three covered indications and confirm ICD-10 alignment before billing |
Aetna Transanal Endoscopic Microsurgery Coverage Criteria and Medical Necessity Requirements 2025
Aetna's transanal endoscopic microsurgery coverage policy covers CPT 0184T under exactly three conditions. Each one requires solid documentation of medical necessity at the time of service.
The three covered indications are:
| # | Covered Indication |
|---|---|
| 1 | Benign rectal tumors (adenomas) — coded most commonly with D12.7, D12.8, or D12.9 (benign neoplasm of rectosigmoid junction, rectum, anus, and anal canal) |
| 2 | Low-risk Tis and T1 rectal carcinoma — coded with D01.1 or D01.2 (carcinoma in situ) or C20 when documented as low-risk stage |
| 3 | Small rectal carcinoids under 2 cm in diameter — coded with D3A.026 (benign carcinoid tumor of the rectum) or C7a.026 (malignant carcinoid tumor of the rectum) |
That size threshold on carcinoids matters. Aetna doesn't just say "rectal carcinoids" — they say under 2 cm. If your documentation doesn't specify lesion size, you're setting up a claim denial before the claim even goes out the door.
The policy does not explicitly state prior authorization requirements within the CPB 0747 text, but that doesn't mean prior auth isn't required for your specific plan. Commercial Aetna products frequently require prior authorization for surgical procedures, including those using CPT 0184T. Check the specific plan's benefit document before scheduling.
Reimbursement for 0184T is available under this coverage policy when the diagnosis codes align with one of the three covered indications and the medical record supports the clinical picture. Mismatched ICD-10 codes are the fastest path to a denial here.
Aetna Transanal Endoscopic Microsurgery Exclusions and Non-Covered Indications
This is where most billing errors will happen. The list of conditions Aetna considers experimental, investigational, or unproven for TEM is long — 18 conditions in total. Several of them are diagnoses that colorectal surgeons genuinely treat with minimally invasive approaches. That makes this list easy to overlook.
Aetna will not cover CPT 0184T for any of the following:
| # | Excluded Procedure |
|---|---|
| 1 | Advanced rectal cancer |
| 2 | Anorectal melanoma (C43.51) |
| 3 | Benign rectal strictures |
| 4 | Colorectal anastomotic stenosis (K56.690–K56.699) |
| 5 | Colovesical fistula |
| 6 | Functional constipation |
| 7 | Giant villous adenoma of rectum (note: D12.7–D12.9 covers this range — see below) |
| 8 | Megacolon (B57.32 and others) |
| 9 | Rectal amyloidoma |
| 10 | Rectal gastrointestinal stromal tumor (C49.A0–C49.A9) |
| 11 | Rectal neuroendocrine tumor in advanced stages or with metastasis (C7a.026 when advanced) |
| 12 | Rectal prolapse and diverticula (K57.x codes) |
| 13 | Rectal schwannoma (D36.15) |
| 14 | Rectal ulcer syndrome |
| 15 | Recto-urinary fistula, including recto-urethral fistula |
| 16 | Recto-vesical fistula |
| 17 | Retro-rectal (pre-sacral) tumors |
| 18 | Tubulo-villous adenoma of the colon |
The giant villous adenoma situation deserves attention. D12.7, D12.8, and D12.9 appear in the ICD-10 code list but are flagged to include giant villous adenoma — which Aetna explicitly excludes. This means the same code range can support a covered claim (benign adenoma) or trigger a denial (giant villous adenoma) depending on the documentation behind it. Your notes need to be specific.
The same tension exists with C7a.026 and D3A.026. Small carcinoids under 2 cm are covered. Advanced or metastatic neuroendocrine tumors are not. Both can map to these codes. Diagnosis code alone won't protect you — the operative report and clinical notes have to draw the distinction.
If you're not sure how to handle the gray-area diagnoses in your mix, loop in your compliance officer before the November 27, 2025 effective date.
Coverage Indications at a Glance
| Indication | Coverage Status | Relevant Codes | Notes |
|---|---|---|---|
| Benign rectal adenomas | Covered | D12.7, D12.8, D12.9 | Excludes giant villous adenoma — document specifically |
| Low-risk Tis rectal carcinoma | Covered | D01.1, D01.2 | Must document as low-risk |
| Low-risk T1 rectal carcinoma | Covered | C20 | Must document as low-risk; advanced rectal cancer not covered |
| Small rectal carcinoids (<2 cm) | Covered | D3A.026, C7a.026 | Size must be documented in clinical record |
| Advanced rectal cancer | Experimental/Not Covered | C20 | Same code as covered T1 — staging documentation critical |
| Anorectal melanoma | Experimental/Not Covered | C43.51 | — |
| Rectal GIST | Experimental/Not Covered | C49.A0–C49.A9 | — |
| Rectal neuroendocrine tumor (advanced/metastatic) | Experimental/Not Covered | C7a.026 | Covered if small and early-stage; not covered if advanced |
| Rectal schwannoma | Experimental/Not Covered | D36.15 | — |
| Colorectal anastomotic stenosis | Experimental/Not Covered | K56.690–K56.699 | — |
| Rectal prolapse / diverticula | Experimental/Not Covered | K57.x | Full diverticular disease range excluded |
| Megacolon | Experimental/Not Covered | B57.32 | — |
| Giant villous adenoma of rectum | Experimental/Not Covered | D12.7–D12.9 | Same code range as covered adenomas — document carefully |
| Benign rectal strictures | Experimental/Not Covered | — | — |
| Colovesical fistula | Experimental/Not Covered | — | — |
| Recto-urinary / recto-vesical fistula | Experimental/Not Covered | — | — |
| Retro-rectal (pre-sacral) tumors | Experimental/Not Covered | — | — |
| Functional constipation | Experimental/Not Covered | — | — |
| Tubulo-villous adenoma of colon | Experimental/Not Covered | — | — |
| Rectal amyloidoma | Experimental/Not Covered | — | — |
| Rectal ulcer syndrome | Experimental/Not Covered | — | — |
Aetna Transanal Endoscopic Microsurgery Billing Guidelines and Action Items 2025
The effective date is November 27, 2025. Here's what to do before and after that date.
| # | Action Item |
|---|---|
| 1 | Audit your open 0184T claims now. Pull all pending and recent claims billed under CPT 0184T for Aetna members. Confirm each one maps to a covered indication — benign adenoma, low-risk Tis/T1 carcinoma, or a carcinoid under 2 cm. Any claim that doesn't have a clear covered diagnosis is a denial risk after November 27, 2025. |
| 2 | Flag the overlapping ICD-10 codes in your charge capture. D12.7, D12.8, D12.9, C20, C7a.026, and D3A.026 can all represent either covered or non-covered conditions depending on staging and tumor size. Add a charge capture alert that requires a documentation note when these codes are paired with CPT 0184T. The coder should not have to guess. |
| 3 | Review operative reports and path reports for carcinoid cases. TEM billing for rectal carcinoids is covered only when the lesion is under 2 cm. If the operative note doesn't state the size, request an addendum before the claim goes out. |
| 4 | Confirm prior authorization requirements with each Aetna plan. CPB 0747 doesn't spell out prior auth, but many Aetna commercial and managed care products require it for surgical procedures. Check the specific plan before scheduling. A missing prior auth is a denial you can't fix after the fact. |
| 5 | Train your surgical schedulers on the covered vs. excluded diagnosis list. Schedulers often don't know that Aetna's TEM billing guidelines exclude giant villous adenoma, rectal GIST, or rectal prolapse. If those procedures get scheduled and coded without a coverage review, the denial comes 60 days after surgery. Update your pre-auth workflow to screen diagnosis against this list. |
| 6 | Update your denial management process for experimental exclusions. If a claim denies on experimental/investigational grounds, consult your compliance team promptly and review Aetna's appeals process under the specific plan. Prevention is cheaper than appeal. |
| Previous Version | Current Version |
|---|---|
| Coverage is considered experimental and investigational for all indications | Coverage is considered medically necessary when specific criteria are met |
| Prior authorization is not required | Prior authorization is required for initial treatment |
| Documentation must include clinical history | Documentation must include clinical history |
| Re-review every 24 months | Re-review every 12 months with updated clinical documentation |
CPT, HCPCS, and ICD-10 Codes for Transanal Endoscopic Microsurgery Under CPB 0747
Covered CPT Codes (When Selection Criteria Are Met)
| Code | Type | Description |
|---|---|---|
| 0184T | CPT | Excision of rectal tumor, transanal endoscopic microsurgical approach (i.e., TEMS), including muscular |
Key ICD-10-CM Diagnosis Codes
The table below includes all diagnosis codes referenced in CPB 0747. Coverage status depends on the specific indication documented — not the code alone.
| Code | Description | Coverage Status |
|---|---|---|
| B57.32 | Megacolon in Chagas' disease | Not Covered |
| C20 | Malignant neoplasm of rectum | Covered (low-risk only) / Not Covered (advanced) |
| C43.51 | Malignant melanoma of anal skin | Not Covered |
| C49.A0–C49.A9 | Gastrointestinal stromal tumor | Not Covered |
| C7a.026 | Malignant carcinoid tumor of the rectum | Covered (<2 cm) / Not Covered (advanced/metastatic) |
| D01.1 | Carcinoma in situ of rectosigmoid junction and rectum | Covered (low-risk) |
| D01.2 | Carcinoma in situ of rectosigmoid junction and rectum | Covered (low-risk) |
| D12.0–D12.6 | Benign neoplasm of colon | Coverage status not explicitly defined for rectal TEM — these are colonic codes; verify with plan before billing with 0184T |
| D12.7 | Benign neoplasm of rectosigmoid junction, rectum, anus, and anal canal | Covered (adenoma) / Not Covered (giant villous adenoma) |
| D12.8 | Benign neoplasm of rectosigmoid junction, rectum, anus, and anal canal | Covered (adenoma) / Not Covered (giant villous adenoma) |
| D12.9 | Benign neoplasm of rectosigmoid junction, rectum, anus, and anal canal | Covered (adenoma) / Not Covered (giant villous adenoma) |
| D36.15 | Benign neoplasm of peripheral nerves and autonomic nervous system of abdomen (rectal schwannoma) | Not Covered |
| D3A.026 | Benign carcinoid tumor of the rectum | Covered (<2 cm) |
| K56.690–K56.699 | Other intestinal obstruction (colorectal anastomotic stenosis) | Not Covered |
| K57.0–K57.5 and subcategories | Diverticular disease of intestine | Not Covered |
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