ICD-10-CM 2027
ICD-10 code for preauricular cyst
From the official ICD-10-CM alphabetic index entry “Cyst (colloid) (mucous) (simple) (retention) › preauricular”. Page updated September 29, 2026.
About coding preauricular cyst
The ICD-10-CM code for preauricular cyst is Q18.1 (Preauricular sinus and cyst).
Within Q18 (other congenital malformations of face and neck), Q18.1 is specifically for preauricular sinus and cyst. Related codes cover sinus, fistula and cyst of branchial cleft (Q18.0), other branchial cleft malformations (Q18.2), Webbing of neck (Q18.3), Macrostomia (Q18.4), Microstomia (Q18.5), Macrocheilia (Q18.6), Microcheilia (Q18.7), other specified congenital malformations of face and neck (Q18.8) and 1 more.
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 154 (Other Ear, Nose, Mouth and Throat Diagnoses with MCC, relative weight 1.5921), DRG 155 (Other Ear, Nose, Mouth and Throat Diagnoses with CC, relative weight 0.9322) and DRG 156 (Other Ear, Nose, Mouth and Throat Diagnoses without CC/MCC, relative weight 0.6659), in MDC 03 (Diseases and Disorders of the Ear, Nose, Mouth and Throat), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about preauricular cyst ICD-10 codes
What is the ICD-10 code for preauricular cyst?
- Q18.1 — Preauricular sinus and cyst.
Is Q18.1 billable?
- Yes. Q18.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can Q18.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict Q18.1 as a principal diagnosis.
Is Q18.1 a CC or MCC?
- No. Q18.1 is neither a CC nor an MCC under MS-DRG v44.0.