ICD-10-CM 2027
ICD-10 code for pylorus hypertrophy
Adult hypertrophic pyloric stenosis
From the official ICD-10-CM alphabetic index entry “Hypertrophy, hypertrophic › pylorus (adult) (muscle) (sphincter)”. Page updated September 29, 2026.
About coding pylorus hypertrophy
The ICD-10-CM code for pylorus hypertrophy is K31.1 (Adult hypertrophic pyloric stenosis). The official index lists 1 more specific code, so check the documentation for details such as type, cause, site or severity before settling on K31.1.
Within K31 (other diseases of stomach and duodenum), K31.1 is specifically for adult hypertrophic pyloric stenosis. Related codes cover acute dilatation of stomach (K31.0), Hourglass stricture and stenosis of stomach (K31.2), Pylorospasm, not elsewhere classified (K31.3), gastric diverticulum (K31.4), obstruction of duodenum (K31.5), fistula of stomach and duodenum (K31.6), polyp of stomach and duodenum (K31.7), other specified diseases of stomach and duodenum (K31.8) and 3 more.
Don't report K31.1 together with the conditions in its Excludes1 note: congenital pyloric stenosis (Q40.0).
As a secondary diagnosis it is a CC (complication or comorbidity), which can move an inpatient stay into the "with CC" MS-DRG of its family, unless the principal diagnosis excludes it.
More specific pylorus hypertrophy codes (official index)
- congenital Q40.0 — Congenital hypertrophic pyloric stenosis
Don't confuse with (Excludes1 for K31.1)
- congenital pyloric stenosis (Q40.0)
Common questions about pylorus hypertrophy ICD-10 codes
What is the ICD-10 code for pylorus hypertrophy?
- K31.1 — Adult hypertrophic pyloric stenosis. More specific codes apply when the documentation supports them: Q40.0.
What is the ICD-10 code for congenital pylorus hypertrophy?
- Q40.0 — Congenital hypertrophic pyloric stenosis.
Is K31.1 billable?
- Yes. K31.1 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can K31.1 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict K31.1 as a principal diagnosis.
Is K31.1 a CC or MCC?
- K31.1 is a CC (complication or comorbidity) under MS-DRG v44.0, unless excluded by the principal diagnosis.