What is the appropriate ICD‑10‑CM diagnostic code for isolated breast pain (mastodynia)?

ICD-10-CM Code for Breast Pain

The appropriate ICD-10-CM diagnostic code for isolated breast pain (mastodynia) is N64.4 (Mastodynia).

Code Specification

The primary code for breast pain is:

• N64.4 - Mastodynia (breast pain)

This code encompasses both cyclical and non-cyclical breast pain when presenting as an isolated symptom without associated masses, nipple discharge, or other suspicious findings.

Clinical Context for Code Selection

When coding breast pain, the clinical presentation guides appropriate documentation:

Cyclical Breast Pain

• Pain temporally associated with the menstrual cycle
• Typically bilateral and diffuse
• Not associated with malignancy 1
• Use N64.4 as the primary diagnosis

Non-Cyclical Breast Pain

• Constant or intermittent pain without menstrual relationship
• May be unilateral or bilateral
• Can be focal or diffuse
• Use N64.4 as the primary diagnosis

Important Coding Caveat

If breast pain occurs with other symptoms (palpable mass, nipple discharge, skin changes), the pain becomes a secondary symptom. In these cases:

• Code the primary finding first (e.g., breast mass, nipple discharge)
• N64.4 can be added as a secondary diagnosis if clinically relevant
• The workup should follow ACR Appropriateness Criteria for the primary symptom, not for isolated breast pain 1

Clinical Significance

Breast pain as an isolated symptom carries extremely low cancer risk (0-3.0% incidence) 1. The ACR guidelines emphasize that cyclical or non-focal/diffuse breast pain is not associated with malignancy 1. When malignancy is present with pain, the pain tends to be well-localized and persistent 1.

Documentation Tips

For accurate coding and clinical management:

• Document whether pain is cyclical vs. non-cyclical
• Note if pain is focal vs. diffuse
• Record presence or absence of palpable abnormalities
• Specify unilateral vs. bilateral presentation
• Include duration and severity using visual analog scale when possible 2

This documentation supports appropriate use of N64.4 and guides whether imaging beyond routine screening is indicated.