Background

Metastases to the breast from extramammary tumours are uncommon, and metastatic renal cell carcinoma to the breast is extremely rare [1]. We report a metastasis to the breast from a renal primary with the radiological and histopathological features.

Case presentation

An 81 years old lady had a right radical nephrectomy in 1999 for conventional renal cell cancer (RCC). She was discharged from the urology and oncology clinics in 2004 after 5 1/2 years follow-up with no signs of local or regional recurrence.

In December 2004, she noticed a lump in the right breast after sustaining a fall. She was referred to the breast clinic in July 2005 for further assessment.

Clinically, she had a mass in the upper outer quadrant of the right breast. The left breast was normal and there was no axillary lymphadenopathy. Abdominal examination was normal.

Radiology confirmed a 17 × 13 × 9 mm well circumscribed hypoechoic mass in the right upper quadrant of the right breast (Figure 1). The mass was core biopsied.

Figure 1
figure 1

Ultrasonography showing hypoechoic mass in the right breast.

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The histopathological examination revealed tumour growth consistent with conventional renal cell carcinoma. Tumour cells strongly expressed vimentin. CT scan of the chest and abdomen showed a 12 mm mass in the right breast and a 2.7 cm metastatic deposit at the right renal bed (Figures 2 and 3). The lungs and the liver were normal. The lump was excised in October 2005.

Figure 2
figure 2

Computed tomography showing well-defined, round mass in the right breast (arrow).

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Figure 3
figure 3

Computed tomography showing tumour mass in the renal bed (arrow points to surgical clips).

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The gross examination of the specimen confirmed metastasis from a renal primary (Figure 4). There was no evidence of in situ ductal or lobular disease.

Figure 4
figure 4

Photomicrograph showing islands of tumour cells with clear cytoplasm, lying in fibrovascular stroma (Hematoxylin & Eosin, 10×).

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The patient was offered Interferon treatment, but she preferred to hold on therapy as an alternative. She is under regular follow-up in the oncology clinic.

Discussion

Metastases to the breast from extramammary primary malignancies are rare. The incidence of metastasis to the breast in various clinical autopsy studies ranges from 5%–6.6% [3]. Both breasts are equally affected and bilateral involvement is not uncommon. Solitary discrete lesions occur in 85% [4].

The primitive neoplasms that most frequently metastasise to the breast are malignant melanoma, lymphoma, lung cancer and in men, prostatic cancer [1–3]. Breast metastasis from a renal tumour is extremely rare, accounting for 3% of the cases.

Clinically, metastatic lesions in the breast present as painless swellings with rapid growth [1, 4]. Unlike primary tumours, the skin is not involved and the axillary node involvement is variable [1, 4].

Mammogram shows well-circumscribed lesions, which lack microcalcifications [1, 4]. The course of renal cell carcinoma is extremely variable and unpredictable both in its clinical development and metastasis [1]. Most patients with renal cell carcinoma following nephrectomy develop multiple metastases and die within 10 years [2].

A preceding history of extramammary carcinoma can be helpful in suspecting a mass as a possible metastasis, as radical surgery can be avoided and appropriate chemotherapy or radiation therapy can be ensured [3, 4].

Conclusion

A treatment strategy for metastatic breast diseases is based on a proper assessment of such cases by surgeons, radiologists and histopathologists.