In the case of histological diagnosis of axillary lymph node metastasis from adenocarcinoma or undifferentiated carcinoma it is very likely that the tumor origin from the breast.
CUPAx represents 0.3-0.5% of all malignant neoplasms of the breast.
It affects women with a mean age of 52.4 years who present with axillary adenopathy.
The first step in the management of occult breast cancer is the histological diagnosis of the metastatic lesion which in the case of CUPAx is represented by axillary lymph nodes.
The pathologist must be in close contact with the clinician; there is no doubt that close collaboration optimizes the possibilities for specific diagnosis.
Second step is the execution of the first level breast imaging such as mammography and sonography using all the applications that allow to increase the diagnostic accuracy.
The third step is the execution of the breast MR,
which can identify in many cases small cancers,
as recommended by the EUSOMA guidelines.
Breast MR makes possible to identify the primary tumor in about 70-80% of cases with negative first level investigations.
It is essential that breast MR is performed by dedicated radiologists with extensive experience in breast imaging and interventional.
The high sensitivity of the breast MR against a lower specificity determines the presence of false positives that must be correctly managed.
In case of CUPAx any area of suspicious enhancement should be typed.
In case of occult MR-only lesion a careful review of the mammogram and second look ultrasound (second US) were performed.
In most cases second US allows to the identification of a target lesion for US-guided core-needle biopsy.
In the other cases MR-guided biopsy is necessary.
Second look and US-guided biopsy or MR-guided breast biopsy allow to diagnosis in 99% cases of suspicious enhancement.
Patients with CUPAx are generally treated with axillary I or II level dissection.
The approved treatments on the breast are mastectomy,
conservative surgery and radiant treatment.
Surgery or breast radiotherapy is not recommended if MR fails to identify the primitive.
Adjuvant chemotherapy or hormone therapy follows the guidelines for stage II breast cancers.
The identification of the primitive tumor improves the possibilities of treatment and prognosis.
Thanks to the improvement of diagnostic techniques and especially to breast MR,
the incidence of CUPAx is decreasing.