Metastatic Renal Cell Carcinoma without Evidence of a Primary Renal Tumour

Abstract

new cases of rcc and 13,500 deaths every year are attributed to this type of renal cancer 1 . In recent decades, the incidence of rcc has been increasing, and the average tumour size at diagnosis has been declining 2 . Those trends are partially attributable to the widespread use of noninvasive abdominal imaging modalities, which have allowed for more incidental findings of asymptomatic tumours. Renal cell carcinoma is about 50% more common in men than in women, and it is unusual in patients under 40 years of age 1 . Several distinct subtypes of rcc have been identified, including the clear cell, papillary, chromophobe, and collecting duct variants 3 . Clear cell rcc, the most common subtype, accounts for 75% of all rcc tumours 2 .Metastatic rcc (mrcc) generally presents with evidence of a primary renal mass, except in cases of metachronous mrcc after nephrectomy for rcc. Here, we present two unusual cases of metastatic clear cell rcc with no evidence of a primary renal tumour. CASE DESCRIPTIONS Patient 1A 70-year-old man was admitted for a fall-induced hip fracture and subsequently underwent arthroplasty. He was readmitted to hospital 8 months later for hypercalcemia and confusion. At that time, computerized tomography (ct) imaging showed bilateral native kidneys in situ; bony lesions in the left scapula, seventh right rib, fifth left rib, and left sternoclavicular joint; and two nodules in the upper lobe of the left lung. There was also destruction of the left pubo-iliac bone from a multi-lobulated lesion (measuring 11 cm) replacing bone, and no evidence of soft-tissue disease (Figure 1).An ABSTRACTAlthough metastases are common in patients with renal cell carcinoma (rcc), it is extremely rare for patients to present with metastatic rcc (mrcc) without evidence of a primary mass in the kidney. Two cases of mrcc with no detectable primary renal mass are reported here. Both patients had bilateral native kidneys in situ and no significant prior urologic history. The first patient presented with a hip fracture and was found to have multiple radiologic bony and lung metastases. Biopsy of a mass involving the pubic bone demonstrated clear cell mrcc. Multiple scans by computed tomography (ct) and confirmatory imaging by magnetic resonance demonstrated no renal mass. This first patient had disease stabilization for 18 months on sunitinib and was still alive at last follow-up. The second patient was diagnosed with clear-cell mrcc after thickened synovium was discovered and biopsied during a knee arthroplasty. Multiple scans by ct in this second patient demonstrated no primary renal mass. Sunitinib and radiotherapy to the knee lesion were initiated, but unfortunately, the patient deteriorated clinically and passed away from disease progression shortly after diagnosis. Because of the rare nature of these cases, a standardized course of action has not yet been established. However, we hypothesize that it is reasonable to manage metastases in these patients by following established mrcc protocols. KEY WORDSMetastatic renal...

Carcinoma of Unknown Primary Site (CUP) With Metastatic Renal-Cell Carcinoma (mRCC) Histologic and Immunohistochemical Characteristics (CUP-mRCC): Results From Consecutive Patients Treated With Targeted Therapy and Review of Literature

“…Seven patients had surgery to treat a solitary metastatic lesion, with no additional systemic treatment provided. 8,9,11,[15][16][17] Eleven patients described in 8 case reports received targeted therapies with sunitinib (n ¼ 6), 6,7,10,18,19 pazopanib (n ¼ 2), 14,19 temsirolimus (n ¼ 2), 12 and everolimus (n ¼ 1). 13 Efficacy data showed that 8 (72%) of 11 patients responded to treatment, and 9 (82%) of 11 were alive when the cases were reported, surviving between 6 weeks and 36 months.…”

“…This entity has only rarely been described in the literature. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] Renal-cell carcinoma (RCC) is a group of cancers arising from the nephron, where 70% of RCC are clear-cell RCC. Because of mutation in the Von Hippel-Lindau gene, a high amount of vascular endothelial growth factor (VEGF) is produced, resulting in increased angiogenesis, cell growth, metabolism, and immunesuppression.…”

Metastatic renal cell carcinoma with undetectable renal mass presenting as lymphadenopathy

“…It still remains unclear how mRCC occurs with an unidentifiable primary lesion; however, there have been several possible explanations [5,6]. The mass could be occult, hence undetectable by imaging modalities.…”

“…However, presenting with mRCC with an undetectable primary is infrequent. A total of 12 cases were documented based on our literature review [5][6][7][8][9][10][11][12]; none of which had diffuse lymphadenopathy metastasizing from an unidentifiable renal primary as presented in our case. In such a challenging situation, immunohistochemical profiling as well as the promising field of molecular genetics aid in reaching a diagnosis.…”

“…Upon reviewing the literature, a total of 12 cases of metastatic kidney cancer had no evidence of a renal mass [5][6][7][8][9][10][11][12]. In this case report, a case of mRCC with an initial presentation of generalized lymphadenopathy with an undetectable primary will be presented.…”