What are the possible causes and recommended evaluation for left-sided chest pain beneath the left breast radiating to the left upper quadrant?

Pain Under Left Breast with LUQ Pain: Evaluation and Management

For pain under the left breast radiating to the left upper quadrant, obtain CT abdomen and pelvis with IV contrast as the primary diagnostic imaging study after excluding breast-specific pathology with clinical examination. 1, 2

Initial Clinical Assessment

The first critical step is distinguishing true breast pain from chest wall or intra-abdominal pathology:

• Breast-specific pain is typically diffuse (>1 quadrant), cyclical, and bilateral—this requires no imaging beyond age-appropriate screening unless focal and persistent 3
• Extramammary pain arises from the chest wall, ribs, or intra-abdominal organs and is interpreted as breast pain—this is the more concerning presentation requiring further evaluation 4, 5
• LUQ abdominal pain suggests splenic, pancreatic, gastric, renal, or colonic pathology requiring cross-sectional imaging 1, 2

Key Clinical Features to Elicit

• Relationship to menstrual cycle: Cyclical pain is almost always benign and physiologic 3, 4
• Focal vs. diffuse: Pain limited to <1 quadrant that is persistent warrants imaging 3
• Associated symptoms: Fever, vomiting, weight loss, or postprandial exacerbation point to intra-abdominal pathology 1, 2
• Chest wall reproducibility: Pain reproduced by palpation of ribs or intercostal muscles suggests musculoskeletal origin 5

Imaging Strategy

When Breast Imaging Is Indicated

Mammography ± ultrasound is appropriate only if:

• Pain is focal (<1 quadrant) and persistent 3
• Patient age >30 years for mammography; ultrasound alone if <30 years 3
• There is an associated palpable mass or nipple discharge 3

Critical caveat: The association between isolated breast pain and malignancy is extremely low (0-3%), so imaging should not be reflexively ordered 3, 6

When Abdominal Imaging Is Indicated

CT abdomen and pelvis with IV contrast (rated 8/9 by ACR) should be obtained if: 1, 2

• Pain radiates to the LUQ or is clearly intra-abdominal in origin 2
• Associated fever, leukocytosis, vomiting, or weight loss 1, 2
• Pain is postprandial with atherosclerotic risk factors (consider mesenteric ischemia) 2
• Rebound tenderness or peritoneal signs are present 2

Why CT with IV contrast is essential:

• Provides comprehensive evaluation of splenic, pancreatic, gastric, renal, and colonic pathology 2, 7
• Alters diagnosis in nearly 50% of cases with nonlocalized abdominal pain 2
• Detects complications requiring urgent intervention (abscess, perforation, ischemia) 1, 2

Laboratory Testing

Obtain before imaging: 1, 2

• Complete blood count (leukocytosis suggests infection/inflammation) 1
• Comprehensive metabolic panel 1
• Pancreatic enzymes (amylase >4× normal or lipase >2× upper limit confirms pancreatitis) 2
• C-reactive protein (CRP >50 mg/L suggests inflammatory process) 2
• Pregnancy test in all women of reproductive age before CT 1, 2

Differential Diagnosis by Location

Pain Primarily Under Left Breast (Chest Wall)

• Musculoskeletal (most common): Costochondritis, rib fracture, intercostal muscle strain 5
• Tietze's disease: Localized costochondral junction tenderness 5
• Spinal root pain: Radiating from thoracic spine 5

Pain Radiating to LUQ (Intra-abdominal)

Most concerning etiologies requiring urgent evaluation: 1, 2

• Splenic pathology: Infarction, abscess, rupture (especially with trauma history) 1
• Pancreatitis: Epigastric/LUQ pain with vomiting, elevated lipase 2
• Gastric pathology: Peptic ulcer, gastritis, perforation 1, 2
• Renal pathology: Pyelonephritis, nephrolithiasis 1, 2
• Splenic flexure colitis/diverticulitis: Less common than sigmoid but possible 2
• Mesenteric ischemia: Postprandial pain with weight loss 2

Management Algorithm

Step 1: Clinical Triage

• Perform focused physical examination distinguishing breast vs. chest wall vs. abdominal origin 3, 5
• Check vital signs for fever, tachycardia, hypotension 1
• Assess for peritoneal signs (guarding, rebound tenderness) 2

Step 2: Risk Stratification

Low-risk features (reassurance ± symptomatic treatment):

• Diffuse, bilateral, cyclical breast pain in premenopausal woman 3, 4
• Reproducible chest wall tenderness without systemic symptoms 5
• No fever, weight loss, or alarm features 1

High-risk features (urgent imaging required):

• Focal, persistent pain with LUQ radiation 3, 2
• Fever, leukocytosis, elevated inflammatory markers 1, 2
• Peritoneal signs, vomiting, inability to tolerate oral intake 2
• Postprandial pain with weight loss (mesenteric ischemia) 2

Step 3: Imaging Decision

If breast-origin suspected:

• Age <30: Ultrasound only if focal and persistent 3
• Age ≥30: Mammography ± ultrasound if focal and persistent 3
• No imaging if diffuse, cyclical, or nonfocal 3

If LUQ/abdominal origin suspected:

• CT abdomen and pelvis with IV contrast (first-line, rated 8/9) 1, 2
• Obtain pregnancy test first in women of reproductive age 1, 2
• Consider ultrasound first if gynecologic pathology suspected in premenopausal women 3

Step 4: Treatment Based on Findings

Benign breast pain:

• Reassurance that cancer risk is <3% 3, 6
• NSAIDs for symptom control 8
• Reserve danazol, tamoxifen, or bromocriptine for severe, refractory cases only due to adverse effects 4

Intra-abdominal pathology:

• Treat according to specific diagnosis identified on CT 1, 2
• Surgical consultation if perforation, abscess, or peritonitis 2
• Antibiotics if infectious/inflammatory process confirmed 1, 2

Critical Pitfalls to Avoid

• Do not obtain breast imaging reflexively for all breast pain—the yield is extremely low without focal, persistent symptoms 3, 6
• Do not miss intra-abdominal pathology by attributing LUQ pain to breast origin—CT changes diagnosis in ~50% of cases 2
• Do not forget pregnancy testing before CT in reproductive-age women—this is a mandatory safety step 1, 2
• Do not rely on clinical examination alone for LUQ pain—misdiagnosis rates are 34-68% without imaging 9
• Do not dismiss postprandial pain with weight loss—this is mesenteric ischemia until proven otherwise 2