Abstract
Metastases to the breast are very uncommon as compared to primary tumours. Breast is an unusual site for metastasis from renal cell carcinoma. Only occasional cases are reported in the literature. These metastases must be clearly diagnosed as the treatment of primary breast cancer and metastases differs markedly. Treatment of isolated metastases from renal cell carcinoma is usually surgical resection. We report two cases of isolated metachronous metastases to breast from renal cell carcinoma.
Introduction
Primary breast cancer is the commonest cancer in women worldwide; this is irrespective of their race or ethnicity [1]. However metastases to the breast are less common, constituting around 0.5%–1.3% of malignant breast tumours. Percentages are reported to be slightly higher in autopsy series ranging from 0.5%–6.6% [2,3]. Renal cell carcinoma (RCC) metastasizing to the breast is a rare event, and only occasional cases are reported in the literature [4,5]. Treatment of metastatic renal cell carcinoma is immunotherapy but isolated metastases can be resected with good outcomes [6]. We report two cases of isolated metachronous metastasis to breast from renal cell carcinoma. Our first case is all the more intriguing as the patient was previously treated for breast cancer and presented with a lump in the same breast near the scar of previous surgery mimicking loco-regional recurrence, thus confusing the clinical picture further.
Case summary 1
A seventy nine years old lady presented in the one stop breast clinic of our hospital with a two week history of having noticed a well-defined lump in her left breast. She had a history of a left sided oestrogen receptor positive Invasive Ductal Carcinoma (IDC) of breast about 12 years ago for which she underwent surgery in form of wide local excision (WLE) with axillary nodal clearance (ANC). All nodes were free of metastasis. She subsequently received radiotherapy to the chest wall followed by 5 years of tamoxifen. About eight years later, she was diagnosed with early endometrial adenocarcinoma and underwent hysterectomy and bilateral salpingo-oophorectomy. Two years after that, she was diagnosed with a Renal Cell Carcinoma (T2N0M0) and underwent left nephrectomy. This was of the classical clear cell type. There was no evidence of distant metastasis at the time of diagnosis. No adjuvant treatment was required as per the stage of the disease. Another year later she noticed a small lump in her left breast over the scar and presented with it in breast clinic.
During this episode examination revealed an obvious gross asymmetry between both the breasts in keeping with the previous surgery on the left breast. The lump was around 3 × 3 cm, non-tender, fixed to the muscle in the left breast and was present close to the well healed radial scar of previous surgery. No lymph nodes were palpable in the draining areas. A well healed scar of previous axillary nodal clearance was present in the axilla.
Clinically, a diagnosis of recurrent / new primary of the left breast was made. The patient underwent mammography (Fig. 1) followed by core biopsy, which surprisingly reported it to be consistent with metastatic RCC. A metastatic work-up, in form of CT thorax, abdomen and pelvis and bone scan revealed no other metastases. The tumour showed the classical morphology of a clear cell carcinoma with packets of clear neoplastic cells surrounded by a fine capillary network. On immunohistochemistry the tumour cells were positive for vimentin, RCC antigen (luminal staining), CD10, with patchy nuclear positivity for P53 but was negative for CK7, CA- 125, ER and WT-1.
Following discussions at the multidisciplinary meeting, a wide local excision of the lesion was performed. Post-operative recovery was uneventful. Histopathology report confirmed it to be a well circumscribed tumour with the classical appearances of a renal cell carcinoma thus compatible with metastatic renal cell carcinoma (clear cell variant). All margins were free of tumour. No further adjuvant treatment was advocated. The lady is currently disease free for last 10 months and under our follow-up.
Case summary 2
An eighty three years old lady had history of Renal Cell Carcinoma (T2N0M0) three years ago and was treated by laparoscopic nephrectomy. No evidence of metastatic disease was present at the time. No further adjuvant treatment was given. She developed isolated port site recurrence two years later which was resected, again presented a year later with lump in her right breast. She had co-morbidities in form of Diabetes Mellitus, asthma and hypothyroidism.
On this occasion, there was a well-defined lump in the upper inner right breast about 1 × 1 cm. Bilateral axillae and supraclavicular regions were normal. The nodularity was clinically indeterminate. Mammogram showed a low density irregular mass about 13 mm × 11 mm and 25 mm from the nipple in the upper inner right breast (Fig. 2). Ultrasound guided needle core biopsy of right breast showed classical features of metastatic Renal Cell Carcinoma of clear cell type (Fig. 3 a,b). The tumour was strongly positive for CD10 and RCC antigens (Fig. 3 c,d) and negative for CK7, CK20, ER and S 100. This immuno-histochemical profile was also in keeping with a RCC.
She underwent staging investigations which showed the breast metastasis to be the solitary lesion. The case was discussed in the Multi-disciplinary meet and decision for surgery was made. Wide Local Excision of the tumour was performed with clear margin reported on histo-pathological report. The lady is currently fine and under urology follow-up for last 5 months.
Discussion
The breast is a common site for primary tumours, but a rare for metastases as there are few cases reported in the literature [2–5]. Even rarer is the event when breast had primary as well as a secondary tumour (as our first case) [5]. Metastasis can occur in synchronous or meta-chronous manner. A study by Bowditch et al claim poor prognosis of synchronous metastasis as compared to meta-chronous metastasis [7]. However, there is inadequate data in the literature to strongly support this statement. The neoplasms that most frequently metastasizes to the breast are malignant melanoma, lymphoma, lung cancer and in men, prostate cancer [2,3]. Breast metastasis from a renal tumour is extremely rare, accounting for 3% of the total metastatic cases [4].
Clinically, metastatic lesions in the breast present as painless swellings with rapid growth. Solitary discrete lesions occur in 85% [4]. Unlike primary tumours, the skin is usually not involved and the axillary node involvement is variable [2–5]. Incidence is similar in both breast and bilateral involvement is not uncommon [9].
Mammographically, the lesion is usually well circumscribed without micro-calcifications. The possibility of the secondary tumour of the breast should be kept in mind in a patient previously treated for malignancy, even though the incidence of primary cancer is much higher in comparison. Pathological assessment is mandatory through biopsy and key for making the diagnosis [10]. It is important in these situations to make the histo-pathologist and other members of multidisciplinary team aware of history of previous malignancies so everyone is alerted to the possibility of metastasis.
Treatment needs to be individualized based on the stage at presentation. Isolated secondary tumour requires excision. Mastectomy and axillary nodal dissection may not be necessary and no adjuvant therapy is recommended. In case of widespread involvement immunotherapy is the cornerstone of management. In these cases, the prognosis is usually poor and most patients succumb to the disease in a year [6].
In conclusion, it is important to bear in mind the possibility of metastases of tumours to the breast particularly in patients with a history of extra-mammary malignancies. Presence of multiple primaries may complicate the management of these cases. Isolated metastasis to breast from renal cell carcinoma can be treated by surgical excision without lymph node dissection in the absence of grossly enlarged nodes.
Funding
Disclosure of Interest statement: The authors acknowledge that there is no financial interest or benefit from this report.