Clinical History
We report a case of an elderly gentleman with a primary diagnosis of colonic carcinoma who on the staging CT scan was found to have a cavernous transformation of the portal vein. We discuss the
causes and CT appearances of this finding.
Imaging Findings
An 82 year old gentleman presented with a two month history of weight loss, malaise, and a palpable left lower abdominal mass. On ultrasound examination, this mass was suspicious of an annular
colonic carcinoma and hence a CT scan of the thorax, abdomen, and pelvis were done for diagnosis and staging. The CT abdomen revealed in additon a cavernous transformation of the portal vein. There
was no past medical history of chronic liver disease. It is believed that the prothrombotic tendency associated with malignancy has predisposed the patient into developing this new finding.
Discussion
Cavernous transformation of the portal vein (CTPV), also known as ‘portal cavernoma’, is defined as formation of venous channels within, or around, a previously thrombosed portal vein. A
leash of fine or markedly enlarged, serpiginous vessels is seen in place of the portal vein. Intrahepatic extension of the cavernous transformation can also be seen. Studies on the natural history of
CTPV suggest that this abnormality develops in days to months following thrombosis of the portal vein. The cavernous transformation can develop as early as 6-20 days of the acute thrombus formation.
The acute thrombotic event may be associated with abdominal pain and fever but often goes unnoticed. Therefore, the diagnosis of portal vein thrombosis is usually not established until patients
present with symptoms of portal hypertension. Two types of collateral circulation can be observed: portosystemic, mainly through the left gastric, and the perisplenic veins (the caput medusae, i.e.
the paraumbilical-to-abdominal venous route, is never seen); and portoportal, from the periportal or pericholecystic venous channels to the intrahepatic portal veins [1]. CTPV occurs in approximately
3% of patients with portal hypertension [2]. The cause of this entity may be congenital or acquired, but frequently it is idiopathic. In adults, the main causes include pancreatitis, pancreatic
carcinoma, alcoholic cirrhosis, extrinsic compression, and direct invasion by periportal tumours and hepatoma. Other causes include hypercoagulable states, intrabdominal inflammatory disease, severe
dehydration, shock, sepsis, and complications of abdominal surgical procedures, including liver transplantation. The long history and follow-up of these patients also suggest that some will develop
adequate collaterals and not experience extensive complications, whereas others develop varices and life-threatening hemorrhage. A study has shown that fifty percent of patients developed significant
hemorrhage and required surgical intervention. A review of CTPV in both adults and children shows the mortality rate from hemorrhage is 5% and the overall mortality rate is 10% [ 3]. CTPV is reported
as having the appearance of a subhepatic spongelike mass. This appearance has also been reported in cases of pancreatic hemangiosarcoma. Bile duct varices are occasionally observed in patients with
portal hypertension. The terms "portal biliopathy" and the "pseudo-cholangiocarcinoma sign" have been used to describe the radiographic changes in the bile duct due to these varices, which may in
turn cause variable degrees of bile duct obstruction [2]
Differential Diagnosis List
Cavernous transformation of the portal vein secondary to thrombosis.
Final Diagnosis
Cavernous transformation of the portal vein secondary to thrombosis.
