Hepatic adenoma and focal nodular hyperplasia: diagnosis and criteria for treatment

Focal nodular hyperplasia (FNH) and adenoma are rare benign hepatic tumors, and the standards for diagnosis and treatment still remain controversial. Usually adenoma is an indication for resection, due to its tendency to bleed and to degenerate; FNH, on the contrary, may be treated conservatively. Preoperation differential diagnosis is, however, difficult, often impossible.

Thirty-eight patients with presumed hepatic adenoma and/or FNH were studied at our department from 1984 to 1996. Preoperative assessment included clinical evaluation and symptoms, laboratory tests, liver biopsy, ultrasound scan, computed tomography scan, magnetic resonance imaging, scintigraphy, and angiography. Thirteen patients had a presumed diagnosis of FNH, 16 of adenoma, and 9 of undetermined benign lesions; 27 had hepatic resections (3 with laparoscopic technique), and 11 were not operated on and are actually under a strict follow-up observation.

The final diagnosis was 19 FNH and 19 adenomas (2 of which contained areas of hepatocarcinoma). Presumed diagnosis was confirmed in 71% of cases. Use of oral contraceptives, abdominal symptoms, and pathologic liver test results were frequent in patients with adenomas. There were no deaths after surgery. All resected patients were tumor free during the follow-up, and in 10 of the 11 nonoperated cases, the size of the nodules remained unchanged. We conclude that precise diagnosis of these benign liver tumors remains difficult and sometimes impossible, despite new imaging techniques. Hepatic resections can be performed under very safe conditions; laparoscopic surgery may play a role in selected cases. Adenomas and uncertain cases are clear indications for surgery. Only when a diagnosis of FNH can be firmly confirmed in asymptomatic patients is strict observation without surgery recommended.