What could be causing pain under the left breast and mid back in a woman?

Pain Under Left Breast and Mid Back in a Woman

This symptom pattern requires systematic evaluation to distinguish between breast-related causes, musculoskeletal/chest wall conditions, and potentially serious extramammary sources including cardiac, pulmonary, or gastrointestinal pathology.

Understanding the Differential Diagnosis

The combination of pain under the left breast with mid-back pain suggests either:

• Extramammary causes (accounting for 10-15% of perceived "breast pain"), which include musculoskeletal conditions, nerve entrapment, or referred pain from cardiac, pulmonary, esophageal, or other visceral sources 1
• True breast pathology with radiating pain
• Musculoskeletal pain from large breast size causing postural strain

Critical Red Flags to Assess Immediately

Cardiac causes must be excluded first given the left-sided location and back radiation. The nerve supply to the breast comes from intercostal nerves T3-T5, and irritation anywhere along their course can cause breast or referred pain 1. Coronary ischemia can present as left breast pain with back radiation 1.

Assess for:

• Exertional component, dyspnea, diaphoresis, nausea (cardiac ischemia) 1
• Pleuritic quality, dyspnea, risk factors for pulmonary embolism 1
• Fever, productive cough (pulmonary infection, pleurisy, tuberculosis) 1
• Dermatomal distribution, vesicular rash (shingles) 1

Musculoskeletal and Chest Wall Causes

The most common benign explanation for this pain pattern is musculoskeletal, particularly in women with large breasts or poor posture.

Specific Conditions to Consider:

• Costochondritis (Tietze syndrome): reproducible tenderness over costochondral junctions 1, 2
• Pectoral muscle strain or spasm: pain with arm movement, history of overuse 1
• Intercostal nerve entrapment: particularly the lateral cutaneous branch of the third intercostal nerve 1
• Cervical or thoracic nerve root syndrome: pain radiating from spine to anterior chest 1
• Rib fracture: history of trauma, point tenderness 1
• Large breast-related strain: chronic postural pain, worse with activity 2, 3

Breast-Specific Causes

Noncyclical Mastalgia

Noncyclical breast pain is more likely to be unilateral and focal, typically affecting women in their fourth decade, though 10-15% present after age 50 1. This type requires evaluation to exclude underlying breast pathology 1.

Specific breast causes include:

• Duct ectasia or secretory calcifications 1
• Mastitis or breast abscess (look for induration, redness, warmth, fever) 1
• Mondor disease (thrombophlebitis of thoracoepigastric vein) 1
• Trauma-related (10% of noncyclical cases) 1
• Post-surgical pain (if prior breast surgery) 1

Cancer Considerations

While pain alone rarely indicates breast cancer (risk 1.2-6.7% when pain is the only symptom), advanced cancers can present with pain as the primary symptom 2, 4. Invasive lobular carcinoma and anaplastic carcinoma are disproportionately associated with pain 1. Deep tumors in large breasts or those with chest wall invasion may present with pain 1.

Visceral Referred Pain Sources

Other serious causes to exclude:

• Esophageal disease: achalasia, hiatal hernia, gastroesophageal reflux 1
• Gallbladder pathology: particularly if pain radiates to back 1
• Peptic ulcer disease 1

Diagnostic Approach

Clinical Examination

Perform focused assessment for:

• Reproducible chest wall tenderness (suggests musculoskeletal cause) 1, 2
• Breast mass or skin changes (requires imaging) 2, 5
• Cardiac examination and vital signs 1
• Respiratory examination 1
• Spinal and paraspinal tenderness 1

Imaging Recommendations

For focal, unilateral breast pain with normal examination:

• Women ≥30 years: diagnostic mammogram with ultrasound 2
• Women <30 years: ultrasound alone 2

For diffuse, non-focal breast pain with normal examination:

• No imaging required; reassurance and symptomatic management 2, 5

Avoid unnecessary imaging for diffuse musculoskeletal pain when clinical exam suggests mechanical pain from large breasts or chest wall conditions 3, 5.

Management Algorithm

First-Line Conservative Measures

For musculoskeletal or breast-related pain:

• Properly fitted supportive bra, especially for women with large breasts 2, 3
• Over-the-counter NSAIDs (ibuprofen) for symptomatic relief 2, 3, 6
• Ice packs or heating pads for comfort 2, 3
• Physical therapy with stretching exercises focusing on upper back muscles and posture 2, 3

Reassurance alone resolves symptoms in 86% of mild cases and 52% of severe cases 2.

When Conservative Measures Fail

If symptoms persist after 6-12 weeks:

• Referral to physical medicine and rehabilitation for intensive therapy 3
• Consider acupuncture (demonstrated effectiveness for musculoskeletal pain) 2, 3
• Topical NSAIDs as second-line therapy 7

Surgical Consideration

For women with large breasts and persistent pain despite conservative measures, therapeutic mammoplasty can address both cosmetic concerns and pain related to breast volume 3.

Critical Pitfalls to Avoid

• Never dismiss left-sided chest pain with back radiation without excluding cardiac ischemia, especially in women with cardiac risk factors 1
• Do not assume all breast pain is benign; some cancers present with pain as the only symptom 1, 2, 5
• Avoid ordering unnecessary imaging for diffuse, non-focal pain when clinical exam is normal 2, 5
• Always consider extramammary causes (10-15% of cases) when breast exam and imaging are normal 1, 2, 5
• Do not overlook pulmonary embolism, which can present as pleuritic chest pain with back radiation 1