ICD-10-CM 2027
ICD-10 code for appendix endometriosis
From the official ICD-10-CM alphabetic index entry “Endometriosis › appendix”. Page updated September 29, 2026.
About coding appendix endometriosis
The ICD-10-CM code for appendix endometriosis is N80.549 (Endometriosis of the appendix, unspecified depth). The official index lists 2 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on N80.549.
Within N80.54, choose N80.549 (unspecified depth) only when documentation doesn't support a more specific option: superficial endometriosis of the appendix (N80.541) and deep endometriosis of the appendix (N80.542).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 391 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders with MCC, relative weight 1.2392) and DRG 392 (Esophagitis, Gastroenteritis and Miscellaneous Digestive Disorders without MCC, relative weight 0.7645), in MDC 06 (Diseases and Disorders of the Digestive System), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
More specific appendix endometriosis codes (official index)
Common questions about appendix endometriosis ICD-10 codes
What is the ICD-10 code for appendix endometriosis?
- N80.549 — Endometriosis of the appendix, unspecified depth. More specific codes apply when the documentation supports them: N80.542, N80.541.
What is the ICD-10 code for deep appendix endometriosis?
- N80.542 — Deep endometriosis of the appendix.
What is the ICD-10 code for superficial appendix endometriosis?
- N80.541 — Superficial endometriosis of the appendix.
Is N80.549 billable?
- Yes. N80.549 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N80.549 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N80.549 as a principal diagnosis.
Is N80.549 a CC or MCC?
- No. N80.549 is neither a CC nor an MCC under MS-DRG v44.0.