ICD-10-CM 2027
ICD-10 code for breast swelling
From the official ICD-10-CM alphabetic index entry “Swelling (of) › breast”. Page updated September 29, 2026.
About coding breast swelling
The ICD-10-CM code for breast swelling is N63.0 (Unspecified lump in unspecified breast).
Within N63, choose N63.0 (unspecified breast) only when documentation doesn't support a more specific option: the right breast (N63.1), the left breast (N63.2), axillary tail (N63.3) and subareolar (N63.4).
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 breast swelling ICD-10 codes
What is the ICD-10 code for breast swelling?
- N63.0 — Unspecified lump in unspecified breast.
Is N63.0 billable?
- Yes. N63.0 is a billable/specific ICD-10-CM code valid for FY2027 (October 1, 2026 – September 30, 2027).
Can N63.0 be used as a principal diagnosis?
- Yes. The Medicare Code Editor doesn't restrict N63.0 as a principal diagnosis.
Is N63.0 a CC or MCC?
- No. N63.0 is neither a CC nor an MCC under MS-DRG v44.0.