Axillary nodes unknown primary

Section: Breast Curriculum: Curriculum, page 15

• 1/300

• 70% with adenocarcinoma in the axilla will have breast cancer

• Most seen on mammogram

• MRI will detect 70% not seen on mammogram

• Treatment is as per palpable axillary nodes in breast cancer

  • If truly no identifiable breast cancer, you can discuss close observation of the breast
    • Most women would feel more comfortable with mastectomy

• Pathology/DDx

  • Cat Scratch Fever – Bartonella – need to biopsy to diagnose
  • Brucellosis – unsterilized milk or meat – blood culture or serology
  • Other viral/ bacterial infection of the arm
  • Lymphoma – fever, night sweats, >10% weight loss
  • Melanoma
  • Rheumatoid arthritis

• Work-up

  • Triple assessment, breast mammogram, USS of LN, FNA of LN
    • If FNA is lymphoid → Flow cytometry of sample ± Core Bx
  • If probable occult breast tumour → MRI
  • If no answer - Excision Biopsy
    • FRESH to lab
      • Piece for micro (3-5mm) not in RPMI
      • Piece for flow cytometry (at least 5mm) in RPMI
      • Piece for cytogenetics (3-5mm) in RPMI
    • Freeze some & process some in formalin for H&E staining
  • Flow cytometry can use immunohistochemistry (gives specific subtype of lymphoma & helps to narrow DDx for malignancies) – use the principle of antibodies binding to cellular antigens (CD20/CD3)
  • Cytogenetics – Chromosomes, FISH
  • CD4 & CD8 immunostains only work on frozen material

• Management

  • Where primary not found should have an axillary dissection, adjuvant systemic Rx
  • Management breast is controversial
    • Can have mastectomy
    • Or breast irradiated
    • Or kept under observation