Consultant Radiologist, Yash Diagnostic Center, Yash Hospital and Research Center, Civil Lines, Kanth Road, Moradabad (UP), India
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| Abstract|| |
Many malignant tumors produce retroperitoneal nodal metastases. However, cystic nodal retroperitoneal metastases are uncommon. Renal cell carcinoma is one of the very few carcinomas that can infrequently produce cystic nodal retroperitoneal metastases. Hence, This is a case of retroperitoneal cystic nodal metastases secondary to renal cell carcinoma, which has been rarely reported in the medical literature
Keywords: Retroperitoneal, Cystic, Metastases, Renal cell carcinoma
|How to cite this article:|
Rastogi R. Retroperitoneal Cystic Metastases from Renal Cell Carcinoma. Saudi J Kidney Dis Transpl 2008;19:244-6
| Introduction|| |
Renal cell carcinoma often produces nodal retroperitoneal metastases in the later stages. These metastatic lymph nodes are usually solid but can be infrequently cystic as well. The cystic nature of the nodes has been attributed to the tumor cells causing obstruction to the flow of the lymph resulting in cystic enlargement of the nodes. Few other tumors are also the cause of such cystic retroperitoneal lymph node metastases.
| Case Report|| |
A 30-year-old female patient presented to our hospital with an abdominal lump of six years duration, which was relatively asymptomatic. One month prior to visiting our hospital, she had an episode of hematuria. Clinical examination of the patient revealed a palpable hard lump in the right lumbar region, which was extending up to the right iliac region. The lump was ballotable. There was no pain or tenderness on palpation.
The patient was then referred to the radiology department for further evaluation of the mass. The radiological examination performed included an ultrasound (US) and contrast-enhanced computerized axial tomography (CECT) of the whole abdomen.
US of the abdomen revealed heterogeneous, hyperechoic mass arising from the lower pole of the right kidney with evidence of multiple foci of calcification with areas of necrosis within the matrix of the mass [Figure - 1]. Besides, two large, round, well marginated, cystic lesions with flimsy internal septations and posterior acoustic enhancement were seen [Figure - 2]; one at the level of the left renal hilum and the other at the level of the aortic bifurcation. The provisional US diagnosis was right renal cell carcinoma with probable cystic retroperitoneal metastases.
The CECT of the whole abdomen revealed an irregular, heterogeneous mass lesion arising from the lower pole of the right kidney with curvilinear and punctate calcification and multiple areas of necrosis [Figure - 3]. There was splaying of the pelvicalyceal system. Rounded masses seen on US appeared cystic with no post-contrast enhancement except for the internal septae, which showed mild to moderate post-contrast enhancement [Figure - 4]. The renal mass was pushing the inferior vena cava and abdominal aorta to the contralateral side. The right renal vein revealed a tumor thrombus.
Based on the US and CT findings, the diagnosis of renal cell carcinoma with cystic nodal retroperitoneal metastases and vascular invasion was suggested.
Patient then underwent radical nephrectomy of the right kidney with simultaneous resection of the retroperitoneal cystic lesions. Histopathological examination of the surgically resected specimen confirmed the renal mass lesion to be renal cell carcinoma of clear cell type and the two cystic lesions were the enlarged, retroperitoneal, metastatic lymph nodes. These nodes revealed lymphangiectasis and lymphatic permeation. This confirmed the radiological diagnosis.
| Discussion|| |
Cystic retroperitoneal nodal metastases are seen in malignancies like melanoma, bronchogenic carcinoma, etc. However, it is rarely seen with renal cell carcinoma . 
The pathogenesis of cystic nodal metastases, as suggested in the literature, is obstruction of the lymphatic vessels draining the kidney by tumor cell especially at the level of the efferent duct of the lymph node. 
Calcified renal cell carcinoma is also a biologically distinct sub-group of renal parenchymal tumors. Most renal cell carcinomas with calcification are relatively large and tend to be localized and histologically well differentiated. 
Very few cases of renal cell carcinoma with cystic retroperitoneal nodal metastases have been reported in the medical literature. Ishii et al reported a case of small clear cell carcinoma with cystic retroperitoneal nodal metastases.  Arai et al reported a case of cystic nodal metastases secondary to Bellini duct carcinoma - a rare variant of renal cell carcinoma. 
In conclusion, cystic masses in a case of renal cell carcinoma in the location of the lymph node should prompt us to make this diagnosis.
| References|| |
|1.||Prokop M, Galansid M. Cystic metastasis: In spiral and multislice computed tomography of the body. Thieme 2004:428. |
|2.||Ishii N, Yonese J, Taukamoto T, et al. Retroperitoneal cystic metastasis from a small clear cell carcinoma. Int J Urol 2001;8(11):637-9. |
|3.||Krieger JN, Snideman KW, Sellgeon GR, et al. Calcified renal cell carcinoma: A clinical, radiographic and pathologic study. J Urol 1979;121(5):575-80. |
|4.||Arai T, Tanaka M, Noto K, et al. Cystic lymph node metastasis caused by a Bellini duct carcinoma. Br J Urol 1997;79 (1):135-6. |
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[Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4]