ICD-10 Code H95.131 – Mucosal cyst of postmastoidectomy cavity, right ear (2026): Diagnosis, Symptoms & Billing Guide
2026 ICD-10-CM Diagnosis Code H95.131 – Mucosal cyst of postmastoidectomy cavity, right ear
What it is
This code identifies a mucosal cyst developing in the postmastoidectomy cavity of the right ear. It refers to a localized cystic lesion in a previously operated mastoid space.
Clinical signs
Clinical features vary; refer to documentation. You may see a cyst described on otologic examination or imaging in the right postmastoidectomy cavity, sometimes with ear fullness or drainage noted in the record.
When to use this code
Use H95.131 when the provider documents a mucosal cyst specifically in the right postmastoidectomy cavity. This is appropriate for follow-up visits, imaging findings, or operative notes that clearly identify the site and laterality. Check documentation if the cyst is not clearly linked to the postoperative mastoid cavity.
Do not use for
Do not use this code for generic postoperative ear findings without a documented mucosal cyst. Do not assume laterality or use it for cysts in other ear locations; check documentation.
Coding tip
Confirm both the postoperative mastoid cavity and right-sided laterality before assigning H95.131.