What is the appropriate diagnosis and treatment for a 41-year-old patient with intermittent sharp pain and burning sensation in the left breast/chest and shoulder area, persistent swollen axillary lymph nodes for 6 months, and new-onset jittery sensations and increased fatigue?

Urgent Diagnostic Workup for Suspected Breast Malignancy

This patient requires immediate breast imaging with ultrasound and diagnostic mammography/tomosynthesis to evaluate for occult breast cancer presenting with axillary metastases, given the 6-month history of persistent axillary lymphadenopathy combined with new constitutional symptoms.

Initial Diagnostic Approach

Imaging Studies Required

• Axillary ultrasound is the first-line imaging modality to characterize the morphologically abnormal lymph nodes, assessing cortical thickness, uniformity, size, shape, and vascularity patterns 1, 2

• Diagnostic mammography or digital breast tomosynthesis must be performed concurrently in this 41-year-old patient to identify any occult breast primary tumor that may have metastasized to the axilla 1

• Ultrasound evaluation of the breast parenchyma is complementary and mandatory, performed at the same time as mammography/tomosynthesis regardless of mammographic findings 1

Tissue Diagnosis

• Ultrasound-guided core biopsy of the abnormal axillary lymph nodes should be performed if morphologically suspicious nodes are identified without characteristic findings of benign processes, especially if no breast abnormality is detected on imaging 1

• Core biopsy is superior to fine needle aspiration for obtaining adequate tissue for histological subtype determination, tumor grade assessment, and ER/PR/HER2 status evaluation 1

Differential Diagnosis Considerations

Malignant Causes (Priority)

• Metastatic breast cancer is the most common malignant cause when cancer is identified in axillary nodes, and occult breast cancer with axillary metastases occurs in less than 1% of breast cancers 2

• Lymphoma (particularly non-Hodgkin's lymphoma) can present with unilateral axillary lymphadenopathy and constitutional symptoms like fatigue 2

Benign Causes (Less Likely Given Duration)

• Reactive lymphadenopathy from infection is the most common benign etiology, but the 6-month duration makes this less probable 2

• Silicone adenitis should be considered only if the patient has current or prior breast implants, producing a characteristic "snowstorm" appearance on ultrasound 1, 2

Clinical Red Flags in This Case

Features Suggesting Malignancy

• Six-month persistence of axillary lymphadenopathy far exceeds the typical duration of reactive adenopathy and warrants aggressive workup 2

• New-onset constitutional symptoms (jittery sensations and increased fatigue) may represent systemic disease progression or paraneoplastic phenomena 3

• Unilateral presentation increases suspicion for malignancy compared to bilateral adenopathy, which more commonly suggests systemic processes 2

Pain Characteristics

• Sharp, intermittent pain with burning sensation and radiation can occur with axillary lymph node metastases from breast cancer, though pain alone should not be assumed to represent malignancy 4

• Pain near the axilla in the breast cancer context requires evaluation for axillary lymph node involvement, as regional lymph node status remains one of the strongest predictors of long-term prognosis 4

Critical Next Steps After Imaging

If Breast Primary is Identified

• Sentinel lymph node biopsy is NOT appropriate if axillary nodes are already clinically or radiographically suspicious; proceed directly to pathologic confirmation via ultrasound-guided biopsy 1, 5

• Complete staging with CT chest/abdomen/pelvis and bone scan is required if breast cancer is confirmed 1

If No Breast Primary is Detected

• MRI breast with and without IV contrast is indicated if biopsy shows axillary metastatic adenocarcinoma from a mammographically and sonographically occult primary breast carcinoma 1

• Consider that occult breast cancer was found in 9 of 17 cases with isolated axillary masses and confirmed cancer, with 5 occurring in the contralateral breast 2

Common Pitfalls to Avoid

• Do not delay imaging and tissue diagnosis by treating empirically with antibiotics for presumed infection given the 6-month duration 2

• Do not assume benign etiology based on pain characteristics alone, as malignant lymphadenopathy can be painful 4

• Do not perform sentinel lymph node biopsy if axillary nodes are already clinically abnormal; this requires full pathologic assessment via core biopsy first 1, 5

• Do not order MRI as the initial imaging study; ultrasound and mammography/tomosynthesis are the appropriate first-line modalities 1