AGENESIS OF THE INFERIOR VENA CAVA IN A PATIENT UNDERGOING RESTORATIVE RECTOSIGMOIDECTOMY FOR COLORECTAL CANCER: A CASE REPORT AND ITS SURGICAL IMPLICATIONS

Case Presentation A 50-year-old male presented with asthenia, weight loss, and hematochezia, symptoms which he attributed to long-standing hemorrhoidal disease. On physical examination, the abdomen was unremarkable, but the patient had grade IV hemorrhoids, varicocele, and a large number of varicose veins in the lower limbs. A colonoscopy revealed a vegetative lesion in the sigmoid colon, and histopathology confirmed adenocarcinoma. A CT scan showed thickening of the sigmoid colon and agenesis of the inferior vena cava (IVC), with collateral venous circulation in the retroperitoneum, mesenteric varices, and perirenal varices. Due to these findings and the risk of bleeding, an open surgical approach was chosen. Intraoperatively, the sigmoid tumor and intense collateral circulation in the retroperitoneum, along with mesenteric vessel engorgement, were observed. The patient underwent rectosigmoidectomy, retroperitoneal lymphadenectomy, and colorectal anastomosis. Despite careful retroperitoneal dissection, the surgery was complicated by higher-than-usual bleeding. The patient had a good postoperative recovery. Histopathological analysis confirmed adenocarcinoma. The patient is currently undergoing adjuvant chemotherapy.

Discussion Malformations of the IVC are estimated to occur in 0.5% of the population. The most common include duplications of the IVC, left-sided positioning of the aorta, interruption of one of its segments (infra-hepatic, pre-renal, renal, or infrarenal), and, very rarely, IVC agenesis, with low prevalence in the literature. The etiology of agenesis is typically embryological defects or intrauterine or perinatal thrombosis. This condition is usually asymptomatic but may present with nonspecific symptoms such as abdominal pain or lead to chronic venous insufficiency and deep vein thrombosis. Diagnosis is often incidental, found on imaging studies or during abdominal surgery. Although rare, IVC abnormalities have significant surgical implications and pose a major challenge for surgeons. Preoperative diagnosis of such anomalies allows the surgeon to plan the surgical approach and, through careful exposure and dissection of the anomalous venous network, avoid severe iatrogenic injuries that could lead to massive bleeding and death.

Conclusion This case highlights the rare diagnosis of IVC agenesis discovered during colorectal cancer staging, which significantly impacted the surgical planning and helped avoid negative outcomes for the patient.

No conflict of interest has been declared by the author(s).

Publication History

Article published online:
25 April 2025