Multiple non-tumorous arterioportal shunts due to chronic liver disease mimicking hepatocellular carcinoma: outcomes and the associated elevation of alpha-fetoprotein.

PURPOSE

To elucidate the morphologic appearance of small non-tumorous arterioportal (AP) shunts mimicking hepatocellular carcinoma on helical computed tomography (CT), their associated outcomes, and their relationship with alpha-fetoprotein levels in patients with chronic liver disease.

MATERIALS AND METHODS

Ten patients with multiple AP shunts on dynamic helical CT were evaluated. A non-tumorous AP shunt was defined as no increase or spontaneous regression in size on follow-up CT scans. The number and shape of shunts more than 5 mm in diameter were studied on a segment-by-segment basis on the initial CT scan, and compared with those on follow-up CT scans. Alpha-fetoprotein levels were measured at the same time as CT scanning was performed.

RESULTS

Ten patients with 86 AP shunts (range 0.5-3.8 cm; mean 1.2 cm) underwent arterial, portal and delayed phase imaging of the entire liver. The AP shunts were geographic (44%), round (33%) or wedge-like (23%) in shape. All shunts changed from high- to iso-attenuation on the delayed phase CT. A follow-up CT (mean 73 days) revealed spontaneous disappearance in all but three (97%) of the 86 AP shunts. Furthermore, 16 new shunts appeared in different segments from the primary ones in four patients. The rapid elevation of alpha-fetoprotein levels to 5-10-fold higher than the baseline level was recognized at the same time as the initial appearance of AP shunts in three patients (30%). Further follow-up CT scans detected solitary hepatocellular carcinomas in four patients at a mean 1283 days after the initial CT. The location of the hepatocellular carcinomas was quite different from those of the initially recognized AP shunts.

CONCLUSIONS

Non-tumorous AP shunts varied in CT appearance and demonstrated iso-attenuation in the delayed phase, most of which disappeared within 4 months. For these multiple small stains in chronic liver disease, periodic follow-up CT is recommended rather than alternative invasive interventions, even though there was an association with rapid elevation of alpha-fetoprotein levels.