What is the appropriate evaluation and management for an elderly patient presenting with a lump under the armpit (axilla)?

Evaluation and Management of Axillary Lump in Elderly Patients

Begin with axillary ultrasound as the primary diagnostic modality to differentiate benign from malignant etiologies, followed by image-guided core needle biopsy for any suspicious findings. 1, 2

Initial Diagnostic Approach

Start with targeted axillary ultrasound rather than mammography or other imaging, as ultrasound effectively distinguishes solid from cystic masses and assesses lymph node architecture in real-time. 1, 3 The American College of Radiology specifically recommends ultrasound as the initial imaging test for evaluating axillary masses, as it can determine whether the mass is a simple cyst, lipoma, or abnormal lymph node requiring further evaluation. 1, 2

Key Ultrasound Features to Assess:

• Benign characteristics: Preserved fatty hilum, smooth margins, oval/kidney-bean shape, uniform cortical thickness 2, 4
• Suspicious features: Loss of fatty hilum, irregular margins, increased cortical thickness, abnormal vascularity pattern 2, 4
• Special findings: "Snowstorm" appearance suggests silicone adenitis from breast implants 2, 4

Critical Clinical Context

Determine whether the adenopathy is unilateral or bilateral, as this fundamentally changes your differential diagnosis and management approach. 2, 4

Unilateral Axillary Mass:

• Higher suspicion for: Metastatic breast cancer (most common malignant cause), localized infection, or isolated lymphoma 2, 4
• In elderly patients with cancer history: Metastatic disease is a critical consideration—gastric cancer can rarely metastasize to axillary subcutaneous tissue, and missing the surgical window leads to poor outcomes 5
• Occult breast cancer: Less than 1% of breast cancers present as isolated axillary adenopathy without detectable breast primary 2, 3

Bilateral Axillary Masses:

• More commonly systemic processes: Lymphoma (particularly non-Hodgkin's lymphoma), autoimmune diseases, systemic infections, or hematologic malignancies 2, 4
• Reactive lymphadenopathy: Most common benign etiology from infections or inflammatory conditions 2, 3

When to Proceed to Biopsy

Perform ultrasound-guided core needle biopsy (not fine needle aspiration) for any morphologically abnormal lymph nodes on ultrasound. 3, 4 Core needle biopsy provides superior sensitivity, specificity, and histological grading compared to fine needle aspiration. 3

Indications for immediate biopsy:

• Loss of normal lymph node architecture on ultrasound 2, 4
• Cortical thickening or asymmetry 2, 4
• Abnormal vascularity pattern 2, 4
• Solid mass without benign features 1, 3
• Rapidly growing mass (as seen with metastatic disease) 5

No biopsy needed if:

• Clearly benign features: simple cyst, normal lymph node with preserved fatty hilum, or lipoma 3, 4
• Return to clinical follow-up only 3

Additional Workup Based on Initial Findings

If biopsy confirms metastatic breast cancer but no primary is evident, proceed to breast MRI with contrast to identify occult primary tumor. 4 MRI detects occult breast cancer in more than two-thirds of patients with suspicious axillary lymphadenopathy and negative mammography. 1

If lymphoma is suspected clinically or on imaging, ensure special pathologic evaluation is requested at time of biopsy. 4

Complement axillary ultrasound with diagnostic mammography in women to evaluate for underlying breast lesions, particularly if ultrasound shows suspicious lymph nodes. 1

Common Pitfalls in Elderly Patients

Do not dismiss rapidly growing masses as benign lipomas—while giant angiolipomas can occur in octogenarians, rapid growth in elderly patients with cancer history should raise immediate concern for metastatic disease. 6, 5 The case of gastric cancer metastasizing to the axilla demonstrates that missing the surgical window due to lack of attention to the mass results in inoperable disease. 5

Avoid fine needle aspiration in favor of core needle biopsy when tissue diagnosis is needed, as core biopsy provides definitive histological diagnosis and allows for immunohistochemical staining. 3, 5

Be aware that silicone adenitis from breast implants (even intact implants) can mimic malignancy on imaging and even show FDG uptake on PET/CT, creating false-positive findings. 2, 4

Special Considerations for Elderly Patients

Assess functional status and comorbidities as part of your evaluation, since treatment decisions in elderly cancer patients depend not only on diagnosis but on functional reserve, life expectancy, and ability to tolerate interventions. 1, 7, 8 However, age alone should not preclude definitive diagnosis—elderly patients deserve accurate tissue diagnosis to guide appropriate palliative or curative treatment decisions. 1, 8

Physical examination should include: Total body skin examination, comprehensive lymph node examination of all nodal basins (cervical, supraclavicular, epitrochlear, inguinal), and assessment for other masses or organomegaly. 1