Varicocele is defined as dilation of the pampiniform venous plexus draining the testicle [3]. Its diagnosis is primarily done by physical exam of the scrotum. Clinically the varicoceles are graded as follows: grade I varicocele (palpable only during Valsalva maneuver), grade II (palpable in the standing position), and grade III (visible without palpation). Among healthy men, the incidence of varicoceles varies from 8 to 22% [3]. Nearly 93% varicoceles occur on the left side, while 25% are bilateral [4]. This occurs due to certain anatomical relationship between left renal vein and left testicular vein.
The etiology of varicoceles is multi-factorial. The common causes for left-sided varicocele include absent or incompetent venous valves, perpendicular insertion of internal spermatic vein into the left renal vein and nut-cracker-like compression of the left renal vein between the aorta and superior mesenteric artery. On the other hand, the insertion of the right spermatic vein into the vena cava in an oblique orientation protects it from the high pressures of the vena cava. The right-sided varicoceles result from impairment of drainage of the spermatic vein either by a thrombus or compression [3, 4].
One clinical consequence of infrequency of solitary right varicocele is that should one be identified, retroperitoneal pathology such as renal tumor should be considered, especially if it is of abrupt onset [4]. While the reported incidence of varicocele in renal cell carcinoma varies from 0.6 to 11.4%, the association of an isolated right varicocele and renal tumors is sparsely documented [5]. Various mechanisms have been described for the formation of right-sided varicocele in association with renal cell carcinoma such as extension of tumor thrombus into the spermatic vein with or without thrombus extending into inferior vena cava, invasion of right renal vein by the tumor causing dilatation of the gonadal vein and obstruction of inflow into duplicated testicular vein due to renal vein thrombus [6,7,8,9]. In the present case of right varicocele is caused by RCC without any involvement of tumor thrombus in IVC, right renal vein, right testicular vein and/or without any IVC compression by the tumor. In our report this patient has an anomalous vein draining the hypervascular right renal tumor to the right testicular vein causing dilatation and tortuosity as demonstrated by the CT angiogram. Parker et al. have reported a similar case where they used a varicocelogram to show increased flow from a venous tributary draining the tumor into the testicular vein resulting in right-sided varicocele [9]. Kulesza et al. [10] have reported an anatomical variation in which a venous tributary from the right pampiniform plexus drains into the right renal vein after traversing through the renal parenchyma and another tributary that drains into the right subcostal vein. They believed that these venous tributaries are remnants of a persistent subcardinal vein and an anastomosis of the supracardinal and subcardinal veins which was enmeshed into the growing metanephros. As these variant veins were found to have no valves, they postulated that these vessels may provide a venous channel for metastasis of renal cancer to the ipsilateral testis or for spread from testicular cancer to the ipsilateral testicle.
Parker et al. [9] documented reduction in the size of the varicocele after nephrectomy along with excision of the lateral venous tributary which was draining into the testicular vein. However, in the present case nephrectomy was not performed as the patient had pulmonary metastases at presentation. The hypervascularity of the tumor and the presence of anomalous veins may have caused hematogenous spread of the tumor resulting in pulmonary metastases in spite of the tumor being less than 7 cm (T1 tumor) and no obvious lymphadenopathy on the CT scan.