ICD-10-CM 2027
ICD-10 code for Mastalgia
From the official ICD-10-CM alphabetic index entry “Mastalgia”. Page updated September 29, 2026.
About coding Mastalgia
The ICD-10-CM code for Mastalgia is N64.4 (Mastodynia).
Within N64 (other disorders of breast), N64.4 is specifically for Mastodynia. Related codes cover fissure and fistula of nipple (N64.0), fat necrosis of breast (N64.1), atrophy of breast (N64.2), Galactorrhea not associated with childbirth (N64.3), other signs and symptoms in breast (N64.5), other specified disorders of breast (N64.8) and disorder of breast, unspecified (N64.9).
It is not a CC or MCC, so as a secondary diagnosis it doesn't change the MS-DRG severity level.
In MS-DRG v44.0, it is part of the grouping logic for DRG 600 (Non-Malignant Breast Disorders with CC/MCC, relative weight 0.9975) and DRG 601 (Non-Malignant Breast Disorders without CC/MCC, relative weight 0.6017), in MDC 09 (Diseases and Disorders of the Skin, Subcutaneous Tissue and Breast), as a principal or secondary diagnosis. The DRG a claim lands in depends on the principal diagnosis, procedures and any CC/MCC secondary diagnoses.
Common questions about Mastalgia ICD-10 codes
What is the ICD-10 code for Mastalgia?
- N64.4 — Mastodynia.
Is N64.4 billable?
- Yes. N64.4 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N64.4 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N64.4 as a principal diagnosis.
Is N64.4 a CC or MCC?
- No. N64.4 is neither a CC nor an MCC under MS-DRG v44.0.