Internal mammary sentinel node metastases in an otherwise lymph-node negative breast cancer patient

Report on a Case of Pure Cribriform Carcinoma of the Breast with Internal Mammary Node Metastasis: Description of the Case and Review of the Literature

Aims and background

Pure ductal invasive carcinoma of the breast is more frequently associated with lymphatic invasion, lymph node involvement and high malignant histological grade than combined forms of breast carcinoma. Internal mammary node metastases are not frequently detected when the axillary nodes are negative.

Patients and methods

We report our experience of a case of pure cribriform carcinoma, associated with an intraductal cribriform component, in which the sentinel axillary nodes were negative, while nodal and perinodal metastasis was detected in one internal mammary lymph node.

Conclusions

Data from the literature show that positive internal mammary nodes are an unusual finding when the axillary sentinel node is negative, especially in cases of cancer with a relatively good prognosis, such as cribriform cases.

[En garde, sentinel node!]

Injection technique and radiocolloid size are two critical parameters that must be carefully selected according to patient presentation and lesion appearance for accurate sentinel node detection in breast cancer. Scintigraphic detection and intraoperative localization are dependent on these parameters. The present clinical case illustrates how much deep intralesional tracer injection bears on our capacity to detect extra-axillary sentinel nodes and how the use of smaller-size radiocolloids may sometimes facilitate sentinel node detection.

Localización del ganglio centinela en cáncer de mama. Inyección periareolar del radiocoloide

Traditional lymphadenectomy is being replaced by sentinel node biopsy in initial management of early stage breast cancer. The aim of this study was to validate the technique in our center, where we perform preoperative lymphoscintigraphy and intraoperative detection of sentinel node, after periareolar radiotracer and peritumoral blue dye injection. Sixty patients, breast cancer stages I and II, were included. Lymphatic mapping was performed the day before surgery, after the administration of 74 MBq 99mTc sulfur colloid in periareolar subdermal tissue. Surgical detection of sentinel node through gamma probe was followed by intraoperative and occasionally delayed biopsies. Finally, full axillary node dissection was completed. Lymphoscintigraphy identified sentinel node in 78% of the patients (47/60): 43 in axilla, 4 in internal mammary chain. Probe guided axillary detection was achieved in 88% (53/60): in every patient with axillar migration in scan, in 9/13 without imaged drainage and in 1/4 with internal mammary chain migration. Sensitivity of blue dye technique was 75% (45/60), the concordance between both procedures being high. Considering both, the overall success rate of surgical detection was 90% (54/60); if we exclude those patients who showed exclusive extraaxillar drainage, the success rate reaches 95%. Malignancy was found in 24% of sentinel nodes removed (13/54); it being the only metastatic axillary node in 4/13. No false negative sentinel nodes were found. Therefore, negative predictive value and accuracy were 100%. These results allow us to validate the technique in our center.