What is the appropriate workup for an axillary (armpit) lump?

From the Guidelines

The appropriate workup for an axillary lump begins with a thorough history and physical examination, followed by ultrasound as the first-line imaging modality, as recommended by the American College of Radiology 1. The initial evaluation should include questions about recent infections, trauma, breast symptoms, systemic symptoms, and risk factors for malignancy. Physical examination should assess the entire breast, axilla, and supraclavicular regions. Some key points to consider in the workup of an axillary lump include:

• Laboratory tests may include a complete blood count and inflammatory markers if infection is suspected
• For women over 30, mammography may be added to evaluate for breast cancer, as suggested by the NCCN guidelines 1
• If the lump appears suspicious on imaging, a fine needle aspiration or core needle biopsy should be performed for definitive diagnosis
• MRI might be considered in specific cases where ultrasound and mammography are inconclusive, such as in the evaluation of axillary lymph nodes with suspected malignancy 1 The differential diagnosis for axillary lumps includes:
• Reactive lymphadenopathy due to infection
• Breast cancer metastasis
• Lymphoma
• Lipoma
• Sebaceous cyst
• Hidradenitis suppurativa
• Cat scratch disease Management depends on the underlying cause, ranging from observation for benign reactive nodes to surgical excision and oncologic treatment for malignant lesions, as outlined in the NCCN guidelines for breast cancer 1. Prompt evaluation is important as axillary lymphadenopathy can be the first sign of breast cancer or other significant pathology, and early detection and treatment can improve outcomes 1.

From the Research

Axillary Lump Workup

The workup for an axillary lump typically involves a combination of imaging studies and tissue sampling procedures. The following are some of the key steps involved in the workup:

• Imaging studies:
  • Ultrasonography (US) is commonly used to evaluate the axilla and guide fine-needle aspiration (FNA) or core needle biopsy 2, 3, 4.
  • Mammography may also be used to evaluate the breast tissue 4.
• Tissue sampling:
  • Fine-needle aspiration (FNA) is a minimally invasive procedure that can be used to sample axillary lymph nodes 2, 3, 5, 6.
  • Core needle biopsy is another option for tissue sampling 5, 4.
  • Open biopsy may be necessary in some cases 5.

Indications for Axillary Imaging

Axillary imaging is typically indicated in patients with:

• Axillary symptoms, such as a palpable lump 4.
• Newly diagnosed breast cancer 2, 3, 6.
• Suspicious axillary lymph nodes on clinical examination 3.

Diagnostic Performance of Axillary US and US-FNA

The diagnostic performance of axillary US and US-FNA has been evaluated in several studies:

• Axillary US alone has a sensitivity of 56.6% and a specificity of 81.0% for detecting axillary lymph node metastasis 6.
• The addition of US-FNA improves the specificity to 95.7% and the positive predictive value to 82.3% 6.
• The sensitivity and specificity of US-FNA are similar between palpable and non-palpable breast cancer groups 6.

Management of Axillary Lumps

The management of axillary lumps depends on the diagnosis:

• Benign lesions may be monitored or treated with conservative management 5.
• Malignant lesions may require surgical intervention, such as axillary lymph node dissection 2, 3, 6.
• The use of preoperative axillary US and US-FNA can help avoid unnecessary sentinel lymph node biopsy in some patients 6.