Absence of right common iliac vein causing suprapubic and scrotal varices in a young athletic man

We have described the case of a 26-year-old man who had presented to his primary care physician with persistent, painful varices across his lower abdomen and bilateral tender scrotal varicoceles, which intensified with exercise. Thorough investigations revealed a congenitally atretic right common iliac vein with right-to-left collateralization of the femoral and internal iliac veins. This shunting resulted in the development of suprapubic and pelvic and gonadal varicosities, which provided a critical venous outflow pathway for his right lower extremity. Heightened vigilance is, hence, paramount if our patient requires future abdominal and urologic procedures. Moreover, the present case has highlighted the importance of considering deep system venous anomalies when determining the differential diagnosis for venous diseases.

The global incidence of congenital vascular malformation is 1.5%, although geographic variations exist. 1 A congenital vascular malformation is an inborn error of vascular morphogenesis, ensuing in true structural anomalies. Although arterial and venous malformations are possible, congenital venous malformations account for two thirds of worldwide cases. Specifically, the congenital absence of the right common iliac vein is a distinctly rare clinical entity, with only a few isolated cases reported in the literature, most of which were discovered during cadaveric dissection. 2,3 Thrombosis or congenital anomalies of the common iliac vein can present as suprapubic varicosities and should prompt further clinical investigation. We have described the case of a congenitally absent right common iliac vein, with persistent right external and iliac veins. As a result, our patient developed a unique collateralization in the pelvic and suprapubic venous systems, resulting in both scrotal and subcutaneous suprapubic varices. The patient provided written informed consent for the report of his case details and imaging studies.

CASE REPORT
The patient, an otherwise healthy 26-year-old man, had presented to his family physician with persistent, uncomfortable varices along his lower abdomen and bilateral scrotum. He described the symptoms as heaviness, swelling, and burning in these regions. These symptoms were exacerbated by large bowel movements or exercise and persisted for w30 minutes after a heavy cardiovascular routine. He had had these symptoms for his entire life; however, they had worsened when he increased his athletic extracurricular activities at the age of Some of the findings were in keeping with common iliac vein occlusion; however, the findings were ultimately indeterminant.
No other retroperitoneal anomalies were identified. Based on these findings, his family physician referred him to vascular

DISCUSSION
Any malformation of the cardinal veins can lead to agenesis of the common iliac veins. 2 Specifically, anomalies of the iliac confluence of the posterior cardinal vein can result in the congenital absence of the right common iliac vein, as was seen in our patient. 2,3 Although previous studies have described the congenital absence of the common iliac veins and their branches, the anatomy of our patient was unique in several aspects. 2,3 He had patent right external and internal iliac veins. Thus, in addition to the right-to-left femorofemoral collateral vessels, he had developed right-to-left internal ilioiliac vein collaterals through his pelvic venous system. As such, he had scrotal varices and suprapubic varicosities. A previously reported pediatric case by Yahyayev et al 3 showed that their patient had congenital absence of the right external and internal iliac veins, in addition to his right common iliac vein. However, in their case, the patient's external genitalia did not have varicosities. Similar to that patient, our patient has an increased risk of iatrogenic injury during abdominal and pelvic surgical procedures, given the presence of pelvic and lower abdominal wall varicosities. 4 The scrotal varicosities also result in increased risk during urologic procedures. 5 The findings of varicosities over the pubic tubercle, with the prominence of superficial veins with sparing of the lower extremities, should raise concerns for central venous occlusion (CVO). In patients without a history of central venous catheterization, a CVO might indicate the presence of extrinsic compression of the venous system, such as lymphoma. 6 Another uncommon cause of CVO is May-Thurner syndrome, which traditionally compresses the left common iliac vein by the right common iliac artery. However, in some cases, the arterial compression can cause right common iliac vein compression. 7 Therefore, it is of paramount importance to rule out the presence of a CVO in patients with suspected common iliac vein thrombosis. 6 The incidence of iliofemoral DVT is far greater in patients with vascular structural anomalies; hence, the distinction between vein compression syndrome and agenesis or atresia of the iliofemoral vessels is important. 6,8 With CVO and subsequent DVT, these patients will be at greater risk of developing post-thrombotic syndrome and chronic venous insufficiency. 9 In patients without a CVO but with congenital venous malformations, such as in our patient, surgical intervention remains the most pressing life-threatening risk. [2][3][4]8 Magnetic resonance imaging modalities, such as MRV, are radiation-free and highly valuable for appreciating the patient's anatomy and ruling out DVT and abdominopelvic masses. 3 The CTV is also suitable, as noted in the present case. Finally, conventional venography remains the reference standard for imaging to investigate atypical venous outflow tracts because it can more accurately demonstrate all collateral pathways that would otherwise be too difficult to discern using either MRV or CTV. In addition to gathering diagnostic information, we could consider performing embolization of the gonadal veins to treat the varicoceles. The benefit of this procedure would be to provide significant symptomatic relief and, in the rare case of infertility, could potential help restore reproductive function. Gonadal embolization in such cases is not completely benign. If an adequately developed collateral network is not present, a serious risk exists of fulminant venous thrombosis, which could require urgent orchiectomy.
Surgeons performing pelvic, urologic, and abdominal surgery should proceed with caution to prevent considerable hemorrhage from iatrogenic injury to the collateral veins. 4