What is the possible cause of swelling and pain in the breast?

Possible Causes of Breast Swelling and Pain

Breast swelling and pain most commonly result from benign hormonal causes (cyclical mastalgia), infection (mastitis/abscess), or musculoskeletal chest wall conditions, but require clinical evaluation to exclude less common malignancies, particularly if pain is focal, unilateral, and persistent. 1

Primary Breast-Related Causes

Hormonal/Cyclical Causes

• Cyclical mastalgia accounts for approximately 70% of breast pain cases and is related to hormonal fluctuations during the menstrual cycle 2
• This pain is typically bilateral or diffusely unilateral, waxes and wanes with the menstrual cycle, and is most common in women in their fourth decade of life 1, 2
• Pregnancy and breastfeeding commonly cause noncyclic breast pain and tenderness that usually resolves spontaneously 1

Infectious/Inflammatory Causes

• Mastitis or breast abscess can cause focal pain with swelling, often preceding induration, redness, warmth, and fever 1
• Mondor disease (thrombophlebitis of the thoracoepigastric vein) may present initially as breast pain and swelling 1
• Periareolar inflammation can occur even in prepubertal children with localized pain and tenderness 3

Noncyclical Breast Pain (25% of cases)

• This pain is usually unilateral, more focal, often located in the subareolar area or lower inner breast, and is predominantly inflammatory rather than hormonal 2
• Noncyclical mastalgia is more common in women in their fourth decade, though 10-15% present after age 50 1
• Spontaneous resolution occurs in up to 50% of patients, but this type requires additional evaluation to exclude underlying benign or malignant lesions 1
• Mammography may reveal duct ectasia or secretory calcifications at the site of pain 1

Trauma-Related Causes

• Noncyclical breast pain relates to trauma in approximately 10% of cases 1
• Post-surgical pain is more common after postoperative infection, hematoma, or when surgeons cut across Langer lines of tension 1
• Breast implants, especially subpectoral placement, can cause pain due to scar formation, nerve regeneration, focal nerve injury, or capsule formation 1

Fibrocystic Changes

• Simple cysts that correlate with focal pain may require drainage for symptom relief 2
• These changes can cause unilateral breast pain and swelling 2

Extramammary (Non-Breast) Causes

Extramammary causes account for 10-15% of "breast pain" cases, as the breast's nerve supply from intercostal nerves T3-T5 means irritation anywhere along their course can cause perceived breast pain 1

Musculoskeletal Causes

• Tietze syndrome (costochondritis) is a common chest wall condition mimicking breast pain 1
• Pectoral muscle strains or spasms, entrapment of the lateral cutaneous branch of the third intercostal nerve 1
• Fibromyositis, fibromyalgia, myalgia, and rib fractures 1
• Spinal nerve root syndrome (cervical or thoracic) 1

Serious Systemic Causes to Exclude

• Coronary ischemia can present as breast pain 1
• Pulmonary disease (pleurisy, pulmonary embolus, tuberculosis) 1
• Esophageal disease (achalasia, hiatal hernia), gastroesophageal reflux, peptic ulcer disease 1
• Gallbladder pathology 1
• Shingles and sickle cell anemia 1

Malignancy Considerations

While pain alone rarely indicates breast cancer, certain presentations warrant heightened concern:

• Advanced cancers may present with breast pain as the only symptom, especially if deep in a large breast or with chest-wall invasion 1
• Invasive lobular carcinoma and anaplastic carcinoma are disproportionately associated with mastalgia compared to other cancer types 1
• The risk of cancer in women presenting with breast pain as the only symptom ranges from 1.2-6.7% 2, 4
• Premenopausal women with severe cyclical pain of long duration may have increased breast cancer risk, with some studies reporting 2.1 to 3.6-fold increased relative risk 1

Medication-Induced Causes

• Oral contraceptives, hormone therapy, psychotropic drugs, and some cardiovascular agents have been associated with mastalgia 5
• Noncyclical breast pain due to various medications is poorly understood and has various presentations 1

Critical Clinical Approach

Any suspicious presentation requires imaging evaluation:

• Focal, unilateral breast pain without additional signs of breast disease may need evaluation to exclude underlying lesions 1
• Diagnostic mammography is the imaging study of choice for women ≥30 years; ultrasound alone for women <30 years 2
• Ultrasound is first-line imaging if a mass is palpable or infection is suspected, avoiding radiation exposure 3, 6
• Any suspicious mass detected on physical examination, mammography, or ultrasonography should be biopsied 5

Common Pitfalls to Avoid

• Never dismiss breast pain without proper evaluation, as some cancers can present with pain alone 2
• Always rule out extramammary causes (costochondritis, cervical radiculopathy, cardiac issues) when breast exam and imaging are normal 7, 2
• Do not order unnecessary imaging for diffuse, non-focal breast pain when clinical exam is normal 2
• For smokers with periductal inflammation and burning pain behind the nipple, always advise smoking cessation 2