Internal mammary lymph node metastases

Case contributed by Giorgio M. Baratelli
Diagnosis almost certain


Follow-up of an asymptomatic breast cancer patient.

Patient Data

Age: 50 years
Gender: Female

Ultrasound scan of the chest wall showed a round, homogeneous hypoechoic and avascular mass of approximately 1 cm. in the 4th intercostal right space, close to the costal cartilage. The appearances are suspicious for a metastasis to the internal mammary lymph node, given the history of breast cancer.

Two years previously, the patient underwent a right modified radical mastectomy with adjuvent chemotherapy (AC x 4 plus Taxol) and hormonal therapy (anastrozole), for a grade 3 invasive ductal carcinoma, stage pT2 (48 mm) pN3a (10/23) M0.

The tumor was positive for estrogen and progesterone receptors and negative for HER2, with a Ki-67 proliferation rate of 35% (Luminal B breast cancer).

Radiotherapy on the chest wall was not performed.


Nuclear medicine

PET-CT shows the nodule is metabolically active, making the diagnosis of metastatic disease most likely.  No other local-regional recurrences or distant metastases  were detected.

Case Discussion

A common site for post-treatment breast cancer recurrence is the chest wall. Approximately 10-35% of patients who have been treated for breast cancer have a loco-regional relapse (i.e. metastasis in the scar and in the axillary, internal mammary, and supraclavicular nodes). Ultrasound of the scar, axilla and chest wall may be useful for surveillance imaging to assess breast cancer loco-regional recurrence, although most guidelines do not support it in asymptomatic women.

The internal mammary lymph node (IMLN) chain is the first site of lymphatic drainage of the breast and is considered high risk for subsequent metastatic disease.

According to the current TNM classification (AJCC 8th staging system), the status of IMLN has a prognostic relevance similar to that of axillary nodes. IMLN metastases are respectively coded with pN1b when detected during sentinel node biopsy (SLNB) and pN2b when observed during clinical examination (including radiologic imaging).

The detection of an isolated breast cancer recurrence is very important because it should be treated with curative intent by complete surgical resection, followed by radiotherapy, or by radiotherapy alone, if surgery is not possible.

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