2027 ICD-10-CM Diagnosis Code Q85.89Other phakomatoses, not elsewhere classified
ICD-10-CM Codes›Q00-Q99›Q80-Q89›Q85
- Billable — Valid for Submission
- CC — Complication or Comorbidity
- Risk Adjusts — HCC 23
- POA Exempt
- Chronic Condition
Q85.89 is a billable ICD-10-CM diagnosis code for other phakomatoses, not elsewhere classified. It is valid on HIPAA claims for fiscal year 2027 (October 1, 2026 through September 30, 2027) and groups to MS-DRG 826 through 830, 843 through 845. As a secondary diagnosis, it counts as a complication or comorbidity (CC) and moves an inpatient stay to a higher severity level within its MS-DRG family. It does not count, however, when the principal diagnosis is one of 6 closely related codes. The code is exempt from POA reporting. In AHRQ's Clinical Classifications Software (CCSR), this diagnosis falls under Other specified and unspecified congenital anomalies.
For Medicare Advantage risk adjustment, Q85.89 maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors) under the V28 model, adding a risk factor of about 0.186 for a community, non-dual, aged beneficiary in payment year 2027.
Code Identity
Code Classification
Present on Admission (POA)Billing
Q85.89 is exempt from POA reporting on inpatient claims to general acute care hospitals. Review the other POA exempt codes in Other congenital malformations (Q80-Q89).
Medicare Risk Adjustment (HCC)Billing
Q85.89 maps to a payment category in the CMS-HCC model used to risk-adjust Medicare Advantage payments. Weights are the published community factors for payment year 2027.
Source: CMS Payment Year 2027 risk adjustment mappings and model software. Weights are relative factors, not dollar amounts; a beneficiary's total RAF also includes demographics and interactions. Browse all CMS-HCC categories.
Approximate SynonymsGuidance
Alternate terms and clinical phrases that map to this code.
- Abnormality of canalization and retrogressive differentiation
- Angiomatosis of meninges
- Basal cell nevus with comedones
- Centrofacial lentiginosis syndrome
- Congenital erector pili hamartoma
- Congenital leptomeningeal angiomatosis
- Congenital rhabdomyomatous mesenchymal hamartoma
- Diffuse smooth muscle hamartoma
- Epidermal nevus syndrome
- Generalized basaloid follicular hamartoma syndrome
- Gingival enlargement due to Sturge-Weber syndrome
- Hamartoma of intestine
- Hamartoma of muscle
- Hamartoma of pilosebaceous apparatus
- Hamartoma of small intestine
- Hemangioma of intracranial structure
- Hereditary cutaneous vascular syndrome
- Hereditary neurocutaneous angiomata
- Perlman syndrome
- Peutz-Jeghers polyps of small bowel
- Peutz-Jeghers syndrome
- Phakomatosis cesioflammea
- Phakomatosis cesiomarmorata
- Phakomatosis pigmentokeratotica
- Phakomatosis spilorosea
- Polyp of small intestine
- Port-wine stain with associated anomalies
- Port-wine stain with oculocutaneous melanosis
- Rhabdomyomatous mesenchymal hamartoma
- SCALP syndrome
- Sebaceous nevus
- Spinal hamartoma
- Sturge-Weber syndrome
- Vascular neurocutaneous syndrome
Instructional NotesGuidance
Instructions from the official ICD-10-CM Tabular List that apply to Q85.89: its own notes plus those printed at Q85.8, Q85, and Chapter 17. A note printed at a category, block or chapter applies to every code under it.
Applicable To
Conditions this code is used for: synonyms of the title or, for "other specified" codes, the conditions assigned to it. The list is not exhaustive.
- Peutz-Jeghers syndrome
- Sturge-Weber(-Dimitri) syndrome
Excludes1
Not coded here: the excluded code is never reported together with this one, unless the two conditions are unrelated.
- Meckel-Gruber syndrome (Q61.9)
Excludes2
Not included here: the excluded condition is not part of this code, but a patient may have both, so both codes may be reported.
Notes
General instructions on how these codes are used.
- Codes from this chapter are not for use on maternal records
Source: CMS ICD-10-CM Tabular List. How to read instructional notes.
Referenced in Other NotesGuidance
Instructional notes printed at other codes that name Q85.89, its category, or a range that includes it.
Index to Diseases and InjuriesGuidance
Alphabetical index entries that point to this code.
encephalotrigeminal Q85.89
Dimitri-Sturge-Weber disease Q85.89
Kraft-Weber-Dimitri disease Q85.89
Phakomatosis See Also: specific eponymous syndromes; Q85.9
specified NEC Q85.89
Syndrome See Also: Disease;
Peutz-Jeghers Q85.89
Sturge-Weber (-Dimitri) Q85.89
Clinical ClassificationClinical
AHRQ’s CCSR groups this code into broader clinical categories.
Clinical InformationClinical
Neurocutaneous Syndromes
a group of disorders characterized by ectodermal-based malformations and neoplastic growths in the skin, nervous system, and other organs.
Code History & ChangesHistory
Replacement Q85.89 replaces the following previously assigned code(s):
- Q85.8 - Other phakomatoses, not elsewhere classified
Questions About Q85.89Overview
What is the ICD-10 code for other phakomatoses, not elsewhere classified?
The ICD-10-CM code for other phakomatoses, not elsewhere classified is Q85.89 (sometimes written as Q8589). It is billable on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
Is Q85.89 (Other phakomatoses, not elsewhere classified) a billable code?
Yes. This is a billable ICD-10-CM code, specific enough to report other phakomatoses, not elsewhere classified on HIPAA-covered claims from October 1, 2026 through September 30, 2027.
What MS-DRG does Q85.89 group to?
When other phakomatoses, not elsewhere classified is the principal diagnosis on an inpatient stay, it groups to MS-DRG 844, 827, 829, 843, 828, 826, 830, 845, with relative weights from 0.8443 to 4.7560 depending on complications. Higher weights mean higher Medicare reimbursement.
Is Q85.89 a CC or MCC?
CMS lists Q85.89 as a CC (complication or comorbidity) for FY 2027. Reported as a secondary diagnosis, it moves the inpatient stay to a higher-weighted DRG within its severity family. It does not count when the principal diagnosis is one of the 6 closely related codes in its exclusion list.
Is Q85.89 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 other phakomatoses, not elsewhere classified on inpatient claims. The code appears in the Other congenital malformations (Q80-Q89) range of the CMS exempt list.
What HCC is Q85.89?
Q85.89 (other phakomatoses, not elsewhere classified) maps to CMS-HCC Category 23 (Prostate, Breast, and Other Cancers and Tumors), commonly written as HCC 23, in the CMS-HCC V28 model used for Medicare Advantage risk adjustment in payment year 2027. It mapped to HCC 12 under the retired V24 model. It also maps in the PACE (CMS-HCC V22), ESRD (V21), and ESRD (V24) models. In the Part D prescription drug model it maps to RxHCC 22.
Does Q85.89 risk-adjust for Medicare Advantage payment?
Yes. When documented and reported on a Medicare Advantage encounter, Q85.89 adds a risk adjustment factor of about 0.186 to the beneficiary's RAF score for a community, non-dual, aged enrollee (published V28 weights range from 0.186 to 0.237 depending on the payment segment). A more severe related category (HCC 17, HCC 18, HCC 19, HCC 20, HCC 21, and HCC 22) supersedes it when both are reported. See the full factor table on the HCC 23 category page.
