Q85.9 Phakomatosis, unspecified

Billable ICD-10-CM code, FY2026. Acts as a Complication or Comorbidity (CC) as a secondary diagnosis. Exempt from present-on-admission (POA) reporting.

Applicable to

• Hamartosis NOS

Applies from Q85 Phakomatoses, not elsewhere classified

Excludes1 (never code together)

• ataxia telangiectasia [Louis-Bar] (G11.3)
• familial dysautonomia [Riley-Day] (G90.1)

Risk adjustment (HCC)

• CMS-HCC V28: HCC 23 — Prostate, Breast, and Other Cancers and Tumors
• CMS-HCC V22: HCC 12 — Breast, Prostate, and Other Cancers and Tumors
• RxHCC V08: HCC 22 — Prostate, Breast, Bladder, and Other Cancers and Tumors
• ESRD V24: HCC 12

MS-DRG index

Defines the logic of DRG(s) 826-828 in MDC 17.

Approximate ICD-9-CM (GEMs)

• 759.6 Other hamartoses, not elsewhere classified (approximate)

Diagnosis Index entries for Q85.9

• Hamartoma, hamartoblastoma
• Hamartosis
• Phakomatosis

Nearby codes

• Q85.8 Other phakomatoses, not elsewhere classified
• Q85.81 PTEN hamartoma tumor syndrome
• Q85.82 Other Cowden syndrome
• Q85.83 Von Hippel-Lindau syndrome
• Q85.89 Other phakomatoses, not elsewhere classified
• Q85.9 Phakomatosis, unspecified (this code)