2026 ICD-10-CM Diagnosis Code Q85.9Phakomatosis, unspecified

ICD-10-CM Codes›Q00-Q99›Q80-Q89›Q85

ICD-10-CM Q85.9
CMSSource: CMS FY 2026 ICD-10-CM dataset · Effective Oct 1, 2025 – Sep 30, 2026

Q85.9 is a billable ICD-10-CM diagnosis code for phakomatosis, unspecified. 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. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified congenital anomalies.

Code Identity

ICD-10-CM Code
Q85.9
Billable Status
Yes — Valid for Submission
Code Describes
Phakomatosis, unspecified
Short Description
Phakomatosis, unspecified
Same as the full description in the CMS dataset.
Parent Code
Q85
Phakomatoses, not elsewhere classified

Code Classification

ChapterQ00-Q99Congenital malformations, deformations and chromosomal abnormalities
SectionQ80-Q89Other congenital malformations
CategoryQ85Phakomatoses, not elsewhere classified
This CodeQ85.9Phakomatosis, unspecified

Present on Admission (POA)Billing

Q85.9 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.

  • Bilateral congenital hamartoma of irises
  • Congenital hamartoma
  • Congenital hamartoma of iris
  • Congenital hamartoma of iris of left eye
  • Congenital hamartoma of iris of right eye
  • Congenital hamartoma of skin
  • Connective tissue nevus of skin
  • Hamartoma
  • Hamartoma of duodenal gland
  • Hamartoma of intestine
  • Hamartoma of small intestine
  • Hamartoma of tongue
  • Heart defect, tongue hamartoma, polysyndactyly syndrome
  • Linear basal cell nevus
  • Neoplasm and/or hamartoma
  • Neurocutaneous syndrome
  • Paving stone nevus
  • Port-wine stain in proteus syndrome
  • Port-wine stain of skin
  • Proteus syndrome

Tabular List NotesGuidance

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

Inclusion Terms

  • Hamartosis NOS

Index to Diseases and InjuriesGuidance

Alphabetical index entries that point to this code.

  • - Phakomatosis - See Also: specific eponymous syndromes; - Q85.9

External Cause of Injuries IndexGuidance

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

    • Hamartoma, hamartoblastoma
    • Hamartosis
    • Phakomatosis

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

Clinical InformationClinical

  • Proteus Syndrome

    hamartoneoplastic malformation syndrome of uncertain etiology characterized by partial gigantism of the hands and/or feet, asymmetry of the limbs, plantar hyperplasia, hemangiomas (hemangioma), lipomas (lipoma), lymphangiomas (lymphangioma), epidermal nevi; macrocephaly; cranial hyperostosis, and long-bone overgrowth. joseph merrick, the so-called elephant man, apparently suffered from proteus syndrome and not neurofibromatosis, a disorder with similar characteristics.

  • Hamartoma

    a focal malformation resembling a neoplasm, composed of an overgrowth of mature cells and tissues that normally occur in the affected area.

  • Hamartoma Syndrome, Multiple

    a hereditary disease characterized by multiple ectodermal, mesodermal, and endodermal nevoid and neoplastic anomalies. facial trichilemmomas and papillomatous papules of the oral mucosa are the most characteristic lesions. individuals with this syndrome have a high risk of breast cancer; thyroid cancer; and endometrial cancer. this syndrome is associated with mutations in the gene for pten phosphatase.

  • Peutz-Jeghers Syndrome

    a hereditary disease caused by autosomal dominant mutations involving chromosome 19. it is characterized by the presence of intestinal polyps, consistently in the jejunum, and mucocutaneous pigmentation with melanin spots of the lips, buccal mucosa, and digits.

  • Proteus Syndrome

    a very rare congenital disorder characterized by the development of multiple cutaneous and subcutaneous lesions including lipomas, nevi, and vascular malformations, associated with partial gigantism or digital overgrowth.

  • Congenital Hamartoma

    a hamartomatous lesion which is present at birth.

Patient EducationClinical

Genetic Disorders

Genetic disorders are health conditions caused by changes (also called mutations or variants) in your genes. Genes are parts of DNA found in your cells that carry instructions for how your body grows, develops, and functions. Many genes tell your body how to make proteins, which are needed for your body to work properly.

The full article covers:

  • What are genetic disorders?
  • What causes genetic disorders?
  • What are the types of genetic disorders?
  • What are the different ways a genetic disorder can be inherited?
  • How are genetic disorders diagnosed?

Read the full article at MedlinePlus

Courtesy of MedlinePlus, a service of the U.S. National Library of Medicine.

Convert Q85.9 to ICD-9-CMHistory

The closest ICD-9-CM equivalents under the General Equivalence Mappings.

ICD-9-CM
759.6 Hamartoses NEC
Approximate The match is approximate rather than exact.

Code HistoryHistory

FY 2016AddedAdded to the ICD-10-CM code setEffective October 1, 2015, the first year of ICD-10-CM.
FY 2017–2025No changes
FY 2026CurrentCurrent code set, no changesEffective October 1, 2025 through September 30, 2026.

Questions About Q85.9Overview

Is Q85.9 (Phakomatoses, not elsewhere classified) a billable code?

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

What MS-DRG does Q85.9 group to?

When phakomatosis, unspecified 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 Q85.9 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 phakomatosis, unspecified on inpatient claims.

What is the ICD-9 equivalent of Q85.9?

Under the General Equivalence Mappings, phakomatosis, unspecified converts to ICD-9-CM 759.6 (hamartoses NEC). The mapping is approximate, so confirm the match fits the documentation.

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.