Teaching Case

An 80-year-old woman with only high blood pressure in her medical history presented to our hospital with dizziness and weight loss of 6 kg in the last 6 months. The blood test results showed increased CRP=70 and leukocytes 15.

The imaging process included a chest X-ray (fig.1) followed by a CT thorax/abdomen/pelvis that revealed pathological findings in the left renal pelvis (fig.3), the right 6th rib (fig.2), and the right breast (fig.2).
Mammography and breast ultrasound showed one suspicious lesion in the breast (fig.4, 5) and one in the axilla (fig.6). Ultrasound-guided core biopsy (fig.7) was taken from the breast lesion.The pathologic diagnosis was challenging, the proliferation had histological features of primary breast carcinoma (IDC). The surgical team proceeded to a wire guided lumpectomy of the right breast (fig.9) with sentinel node excision. Meanwhile, an anterograde renal biopsy was performed (fig.8) that showed transitional cell carcinoma of the renal pelvis (fig.10a, b, c). The pathologists took under consideration the possibility that the breast and axillary lesions were metastases from the TCC so they used histopathologic and immunohistochemical examinations for their final diagnosis: metastatic TCC in both breast and axilla (fig.11a, b, c).
The therapeutic approach included laparoscopic nephrectomy and open surgery-nefrouretectomy.

Metastases to the breast from non-mammary primary tumours are uncommon and vary between 0.2% and 1.3%. Higher frequencies of 2–7% are seen in postmortem studies [2].
Women are affected five to six times more frequently than men. No clear predisposing factors correlating with the development of breast metastases have been identified [1].

Metastases to the breast from non-mammary malignancies are rare and show pathologic features of primary tumours. It is usually presumed to be a primary breast carcinoma. Histopathologic features and clinical history in conjunction with the immunohistochemical results should be considered in differentiating a secondary mass from a primary breast carcinoma [3].

Clinically, the metastatic lesions are not distinct from primary tumours: the patient presents with palpable mass/masses which are most often located in the upper outer quadrant of the breast. Multiple, diffuse and bilateral involvement is rare. Also relatively rare is the involvement of the axillary nodes [5].
Among metastatic lesions to the breast, carcinoma of the opposite breast, multicentric lymphoid malignancies, and disseminated melanoma constitute the most likely sources. Other, less common sources are carcinomas of the lung, ovary, or stomach, and, infrequently, carcinoid tumours, hypernephromas, and carcinomas of the liver, tonsil, pleura, pancreas, cervix, perineum, endometrium, and bladder. Regarding children and adolescents, rhabdomyosarcoma is one of the common tumours reported to give rise to breast metastasis. Other neoplasms are leukemia, lymphoma, Ewing sarcoma, neuroblastoma, and yolk sac tumour. Metastases to the male breast is also very infrequent but has been reported in prostatic adenocarcinoma [1].
On mammography, metastatic lesions may manifest as single or multiple masses or as diffuse skin thickening. The metastatic lesions usually appear as round masses with circumscribed or ill-defined borders. They typically lack spiculation. Microcalcifications are rare but can occur with some primary type (e.g. psammoma bodies in ovarian cancer)[5].
On ultrasound, metastatic masses appear hypoechoic with circumscribed margins and, occasionally, posterior acoustic enhancement. Colour Doppler interrogation more often shows increased vascularity [1, 6].
In conclusion, metastases to the breast and/or axilla represent an important diagnostic consideration as these patients have a poor prognosis [1-5], with more than 80% dying within 1 year [1].
This poor survival is due to the fact that at the time of the discovery of the breast lesion, the majority of the patients already have widely metastatic disease.
So, reaching the correct diagnosis is crucial in order to avoid unnecessary procedures and treatments in these patients [1, 2].