Intrahepatic portal vein aneurysm—a rare entity

A20-year-old man was referred for abdominal ultrasound (US) examination as a part of diagnostic workup for anemia. The patient was nondiabetic and nonhypertensive and reported no history of any other chronic illness. There was no history of hemetemesis, jaundice, liver disease, trauma, or surgical intervention. Physical examination of the patient was unremarkable except for pallor. No sign of portal hypertension was found. Routine hematologic investigations were within normal limits except for anemia with a hemoglobin level of 9 g/dl. Grayscale and color Doppler US examination revealed a well-defined fusiform dilatation of the left branch of the portal vein (Figure 1), with nonpulsatile, monophasic venous flow (Figure 2). The size of the lesion was 21 3 17 3 22 mm and there was no evidence of thrombosis or calcification. CT scan was performed to rule out any other associated abnormality and confirmed the US findings with no evidence of thrombosis (Figure 3). There was no associated portal vein branching variation. As the condition was asymptomatic and discovered incidentally, routine follow-up was recommended. The lesion was stable after 6 months. As there are no standard protocols for follow-up of such lesions, we recommended continued follow-up every 6 months. The patient’s anemia was apparently unrelated and of nutritional origin, as his hemoglobin level returned to normal after 6 months of iron and folic acid administration. Intrahepatic portal venous aneurysm is an extremely uncommon entity with unknown etiology, although portal hypertension, trauma, pancreatitis, and interventional procedures have been reported as possible causative factors. Portal vein aneurysms account for 3% of all venous aneurysms with a prevalence of 0.43%. As none of the above-mentioned conditions were present in our case, this aneurysm was likely congenital. This condition has no gender predilection and is usually seen in the fifth to sixth decades of life. Aneurysms have been reported in all parts of the portal vein; however, extrahepatic aneurysms are by far more common than intrahepatic aneurysms. Grayscale and color Doppler US examination is a reliable modality to detect and monitor the growth of such aneurysms. On grayscale US, they appear as well-defined anechoic masses, usually near the porta hepatis. Color Doppler imaging can help differentiate these images from simple hepatic cysts and other FIGURE 1. Grayscale transabdominal US shows a well-defined anechoic structure near the porta hepatis, involving the left branch of the portal vein, without any visible calcifications or thrombus.