ICD-10-CM 2027
ICD-10 code for breast lump
From the official ICD-10-CM alphabetic index entry “Lump › breast”. Page updated September 29, 2026.
About coding breast lump
The ICD-10-CM code for breast lump is N63.0 (Unspecified lump in unspecified breast). The official index lists 16 more specific codes, so check the documentation for details such as type, cause, site or severity before settling on N63.0.
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.
More specific breast lump codes (official index)
- axillary tail
- left N63.32 — Unspecified lump in axillary tail of the left breast
- right N63.31 — Unspecified lump in axillary tail of the right breast
- left
- lower inner quadrant N63.24 — Unspecified lump in the left breast, lower inner quadrant
- lower outer quadrant N63.23 — Unspecified lump in the left breast, lower outer quadrant
- overlapping quadrants N63.25 — Unspecified lump in the left breast, overlapping quadrants
- unspecified quadrant N63.20 — Unspecified lump in the left breast, unspecified quadrant
- upper inner quadrant N63.22 — Unspecified lump in the left breast, upper inner quadrant
- upper outer quadrant N63.21 — Unspecified lump in the left breast, upper outer quadrant
- right
- lower inner quadrant N63.14 — Unspecified lump in the right breast, lower inner quadrant
- lower outer quadrant N63.13 — Unspecified lump in the right breast, lower outer quadrant
- overlapping quadrants N63.15 — Unspecified lump in the right breast, overlapping quadrants
- unspecified quadrant N63.10 — Unspecified lump in the right breast, unspecified quadrant
- upper inner quadrant N63.12 — Unspecified lump in the right breast, upper inner quadrant
- upper outer quadrant N63.11 — Unspecified lump in the right breast, upper outer quadrant
- subareolar
- left N63.42 — Unspecified lump in left breast, subareolar
- right N63.41 — Unspecified lump in right breast, subareolar
Common questions about breast lump ICD-10 codes
What is the ICD-10 code for breast lump?
- N63.0 — Unspecified lump in unspecified breast. More specific codes apply when the documentation supports them: N63.32, N63.31, N63.24, N63.23 and others below.
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.