Mastalgia

Mastalgia is breast pain. It is an extremely common presenting complaint, affecting a substantial proportion of women at some point during their reproductive years.

It is classified into cyclical mastalgia (pain related to the menstrual cycle) and non-cyclical mastalgia (pain unrelated to the menstrual cycle). Cyclical mastalgia is the commoner pattern.

Non-cyclical mastalgia has a more diverse range of causes, including musculoskeletal chest wall pain, which is frequently mistaken for a primary breast source.

The clinical priority is to characterise the pain pattern accurately. This guides reassurance and, in the minority of women who are more significantly affected, targeted symptomatic management.

Classification and pathophysiology

• Cyclical mastalgia generally reflects hormonally-mediated fibrocystic breast changes. It presents as bilateral, diffuse breast pain and tenderness, most prominent in the luteal phase of the menstrual cycle and improving after the onset of menstruation.
• Non-cyclical mastalgia has a more heterogeneous range of causes.
• True breast-origin pain reflects causes such as mammary duct ectasia, a breast cyst or, uncommonly, malignancy. Breast cancer is a rare cause of isolated breast pain without a palpable abnormality.
• Very commonly the pain arises from an extramammary source but is perceived as breast pain, most notably costochondritis and other musculoskeletal chest wall pain. This explanation is common and frequently underrecognised.
• Medication-related mastalgia is particularly associated with hormonal contraception and hormone replacement therapy, and less commonly with certain psychotropic medications. Ask specifically about medication.

• Cyclical mastalgia presents with bilateral, diffuse breast heaviness, tenderness and aching. It is most prominent in the days before menstruation and improves substantially or resolves after onset. It often accompanies the nodularity of fibrocystic breast changes.
• Non-cyclical mastalgia has no characteristic relationship to the menstrual cycle. It is often unilateral or localised to a discrete area of the breast, rather than the diffuse, bilateral pattern of cyclical mastalgia.
• Careful clinical assessment is essential to distinguish true breast-origin pain from musculoskeletal chest wall pain perceived as breast pain, because the distinction bears directly on management.
• Musculoskeletal chest wall pain is frequently mistaken for primary breast pain. It characteristically shows reproducible tenderness on direct palpation of the chest wall or costochondral junctions, rather than diffuse breast tissue tenderness.
• Musculoskeletal pain may be exacerbated by specific movement or positioning. These are important distinguishing features.
• The substantial majority of women with mastalgia of either pattern do not have an underlying malignancy. Breast pain without a palpable lump or other concerning feature has a very low likelihood of being malignant, which is an important reassuring principle for counselling.

• A clinical history carefully characterises the pain pattern: cyclical versus non-cyclical, unilateral versus bilateral, and any relationship to movement, medication use or menstrual cycle timing.
• Breast and chest wall examination assesses for any discrete, palpable breast abnormality and for reproducible chest wall tenderness suggesting a musculoskeletal origin. History and examination are the essential foundation of assessment.
• Where there is no discrete, palpable breast abnormality and the pain pattern is characteristic of cyclical mastalgia or musculoskeletal chest wall pain, further breast imaging is generally not required. A normal clinical examination is substantially reassuring in this context.
• Where any discrete, palpable abnormality is identified, or the pain pattern is atypical, persistent or associated with another concerning feature, triple assessment is warranted to exclude an underlying structural cause.

• Reassurance is the cornerstone of management for the great majority of presentations. It is grounded in the low likelihood of malignancy underlying isolated breast pain without a palpable abnormality.
• Explain the identified mechanism clearly, whether cyclical hormonal change or musculoskeletal chest wall origin.
• A well-fitting, supportive bra, worn consistently including during physical activity and, for some women, overnight, is a simple, valuable, evidence-supported first-line measure for cyclical mastalgia.
• Simple analgesia provides effective symptomatic relief for many women. Options are paracetamol or a topical nonsteroidal anti-inflammatory preparation applied to the affected area. Topical preparations have the advantage of reduced systemic exposure compared with oral treatment.
• For musculoskeletal chest wall pain, management follows the general principles for that presentation. These include appropriate analgesia and, where a precipitating activity or posture is identifiable, activity modification.
• For severe, persistent cyclical mastalgia that significantly affects quality of life and does not respond adequately to simple measures, further pharmacological options may be considered after discussion of risks and benefits.
• Evening primrose oil has modest, though somewhat inconsistent, evidence of benefit.
• For severe, refractory cases, hormonal treatment (tamoxifen or danazol) is used off-label for this indication under specialist guidance, given their adverse effect profiles.
• Patient education covers the generally benign, though sometimes significantly troublesome, nature of mastalgia. It includes clear guidance on when further assessment is warranted, including development of any new, discrete palpable lump or other concerning feature.