ICD-10-CM 2027
ICD-10 code for Micromastia
From the official ICD-10-CM alphabetic index entry “Micromastia”. Page updated September 29, 2026.
About coding Micromastia
The ICD-10-CM code for Micromastia is N64.82 (Hypoplasia of breast).
Within N64.8 (other specified disorders of breast), N64.82 is specifically for hypoplasia of breast. Related codes cover ptosis of breast (N64.81) and other specified disorders of breast (N64.89).
Don't report N64.82 together with the conditions in its Excludes1 note: congenital absence of breast (Q83.0) and hypoplasia of native breast in relation to reconstructed breast (N65.1).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
Don't confuse with (Excludes1 for N64.82)
Common questions about Micromastia ICD-10 codes
What is the ICD-10 code for Micromastia?
- N64.82 — Hypoplasia of breast.
Is N64.82 billable?
- Yes. N64.82 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N64.82 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N64.82 as a principal diagnosis.
Is N64.82 a CC or MCC?
- No. N64.82 is neither a CC nor an MCC under MS-DRG v44.0.