2026 ICD-10-CM Diagnosis Code Q85.81PTEN hamartoma tumor syndrome

ICD-10-CM Codes›Q00-Q99›Q80-Q89›Q85

ICD-10-CM Q85.81
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q85.81 is a billable ICD-10-CM diagnosis code for PTEN hamartoma tumor syndrome. It is valid on HIPAA claims for fiscal year 2026 (October 1, 2025 through September 30, 2026) and groups to MS-DRG 826 through 830, 843 through 845. The code is exempt from POA reporting. Coders also document this condition as cowden syndrome. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified congenital anomalies.

Code Identity

ICD-10-CM Code
Q85.81
Billable Status
Yes — Valid for Submission
Code Describes
PTEN hamartoma tumor syndrome
Short Description
PTEN hamartoma tumor syndrome
Same as the full description in the CMS dataset.
Parent Code
Q85.8
Other phakomatoses, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ80-Q89Other congenital malformations
CategoryQ85Phakomatoses, not elsewhere classified
This CodeQ85.81PTEN hamartoma tumor syndrome

Present on Admission (POA)Billing

Q85.81 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review other POA exempt codes.

Approximate SynonymsGuidance

Alternate terms and clinical phrases that map to this code.

  • Cowden syndrome
  • Proteus like syndrome
  • PTEN hamartoma tumor syndrome

Tabular List NotesGuidance

Coding notes and annotation back-references applicable to this code.

Inclusion Terms

  • PHTS
  • PTEN related Cowden syndrome

Code Also

  • , if applicable, genetic susceptibility to malignant neoplasm Z15.0

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

External Cause of Injuries IndexGuidance

References for this code in the External Cause of Injuries Index.

    • PHTS
    • Syndrome
      • Cowden
        • PTEN related
    • Syndrome
      • PTEN (hamartoma) tumor

Clinical ClassificationClinical

AHRQ’s CCSR groups this code into broader clinical categories.

CCSR MAL010
Other specified and unspecified congenital anomalies
Default principal diagnosis: inpatient Yes · outpatient Yes

Code History & ChangesHistory

Replacement Q85.81 replaces the following previously assigned code(s):

  • Q85.8 - Other phakomatoses, not elsewhere classified
FY 2023AddedAdded to the ICD-10-CM code setEffective October 1, 2022.
FY 2024RevisedCode revised
FY 2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q85.81Overview

Is Q85.81 (Other phakomatoses, not elsewhere classified) a billable code?

Yes. This is a billable ICD-10-CM code, specific enough to report PTEN hamartoma tumor syndrome on HIPAA-covered claims from October 1, 2025 through September 30, 2026.

What MS-DRG does Q85.81 group to?

When PTEN hamartoma tumor syndrome is the principal diagnosis on an inpatient stay, it groups to MS-DRG 826, 827, 828, 829, 830, 843, 844, 845, with relative weights from 0.8516 to 4.6778 depending on complications. Higher weights mean higher Medicare reimbursement.

Is Q85.81 exempt from POA reporting?

Yes. CMS lists this code among those exempt from present on admission reporting, so hospitals do not assign a POA indicator for PTEN hamartoma tumor syndrome on inpatient claims.

Footnotes

[1] Chronic - a chronic condition code indicates a condition lasting 12 months or longer and its effect on the patient based on one or both of the following criteria:

  • The condition results in the need for ongoing intervention with medical products,treatment, services, and special equipment
  • The condition places limitations on self-care, independent living, and social interactions.