Adenoma and focal nodular hyperplasia

B artolozzi C, Lencioni R, Paolicchi A, et al. Differentiation of hepatocellular adenoma and focal nodular hyperplasia of the liver comparison of power Doppler imaging and conventional color Doppler sonography. EurRadiol 1997 7 1410-1415. 

Benign liver tumors (hepatocellular adenoma and focal nodular hyperplasia) are extremely rare conditions that appear to be related to oral contraceptive use (212). 

Hepatic adenomas and focal nodular hyperplasia dynamic CT study Radiology 1986 160 53-58... 

H. Technetium-99m DISIDA hepatobiliary agent in diagnosis of hepatocellular carcinoma, adenoma, and focal nodular hyperplasia. J. Nucl. Med. 1989 30 1278-1279... 

As regards the neoformation of benign tumours, distinction is made between nodular adenoma and focal nodular hyperplasia (FNH). Because there are several transitional types between these two forms, they are generally regarded as variants of the same basic type of tumour (H.-W. Altmann, 1980). Both types may be multiple, (s. tab. 29.10)... 

Bioulac-Sage P, Balabaud C, Bedossa P, et al. Pathological diagnosis of liver cell adenoma and focal nodular hyperplasia Bordeaux update. J Hepatol. 2007 46 521-527. 

Beets-tan RGH, Van Engelshoven JMA, Greve JWM (1998) Hepatic adenoma and focal nodular hyperplasia MR findings with superparamagnetic iron oxide enhanced MRI. Clin Imaging 22 211-215... 

Friedman LS, Gang DL, Hedberg SE, et al (1984) Simultaneous occurrence of hepatic adenoma and focal nodular hyperplasia report of a case and review of the literature. Hepatology 4 536-540... 

Hepatic adenoma is a benign tumour largely affecting women of childbearing age. There is a confusion in the terminology of the lesion and the cases are variously described as having benign haematoma, hamartoma, hepatoma, and focal nodular hyperplasia. Sherlock finds the terms adenoma and focal nodular hyperplasia equally appropriate. 

The following lesions may be hypoechoic (7.) metas-tases, (2.) liver cell carcinoma, (3.) adenomas, (4.) focal nodular hyperplasia, (5.) abscesses, (6.) haematomas, (7.) early liver infarction, (S.) foci showing reduced fatty infiltration, (9.) lymphomas, and (10.) lipomas. In individual cases, differentiation between a benign and a malignant structural defect may cause considerable difficulties. (59) (s. fig. 9.4)... 

Hepatic adenoma consists of atypical, strand-like hepa-tocytes. It is characterized by normal perfusion and an extensive absence of Kupffer cells as well as irregularity of the bile ducts. Scintigraphically, it is possible to demonstrate that there is no elimination of iminodiacetates from the adenoma and that uptake of the radioactive tracer is prolonged compared with the normal liver parenchyma ( trapping on IDA scans). (38) No colloidal albumin or Tc-colloid is taken up - this allows differentiation of an adenoma from focal nodular hyperplasia. The use of the SPECT technique increases sensitivity. 

Adenoma cells are arranged in cords and separated by sinusoids (Ishak 1994). The tumor lacks portal tracts or bile ducts, a key histological feature that helps distinguish hepatocellular adenoma from focal nodular hyperplasia (Boulahdour et al. 1993). Kupffer s cells are found in adenomas but probably they are often decreased in number or less functional than normal liver tissue, as reflected by absent or diminished uptake of technetium (Tc)-99m sulfur colloid (Fig. 10.1) (Rubin and Lichtenstein 1993). Because this neoplasm has no portal tracts, the tumor perfusion occurs solely by peripheral arterial feeders therefore the hypervascular nature of adenoma, related to sinusoids and feeding arteries, associated with poor connective tissue support, can lead frequently to hemorrhage. Because a tumor capsule is usually absent or incomplete, hemorrhage may spread into the liver or abdominal cavity (Molina and ScHiFF 1999). 

Hepatic lesions (adenomas, focal nodular hyperplasia, hepatocellular carcinoma, etc) Rarely, benign and malignant hepatic adenomas have been associated with the use of hormonal contraceptives. Severe abdominal pain, shock, or death may be due to rupture and hemorrhage of a liver tumor. 

Oral contraceptives, estrogens, and benign liver tumors The effects of oral contraceptives on the liver include not only benign liver tumors (focal nodular hyperplasia, hepatic adenoma, and hemangioma) (74) and hepatocellular carcinoma, but also peliosis hepatis (75), sinusoid dilatation (76), and such probably unrelated shorter-term complications as jaundice and gallstones. 

Marks WH, Thompson N, Appleman H. Failure of hepatic adenomas (HCA) to regress after discontinuance of oral contraceptives. An association with focal nodular hyperplasia (FNH) and uterine leiomyoma. Ann Surg 1988 208(2) 190-5. 

Focal nodular hyperplasia FNH is the most common benign hepatic neoplasia. As with adenoma, it may develop after the patient has taken oestrogens for a longer period (usually more than 4 or 5 years). In some cases, the lesion develops within 6 to 12 months after intake begins. (13, 125) en the oral contraceptives are discontinued, the tumour regresses or disappears (completely). The rate of both oestrogen-induced hepatocellular adenoma and FNH was considerably reduced after the introduction of low-dose oral contraceptives. 

Ruppert-Kohlmayr AJ, Uggowitzer MM, Kugler C, Zebedin D, Schaffler G, Ruppert GS (2001) Focal nodular hyperplasia and hepatocellular adenoma of the liver differentiation with multiphasic helical CT. AJR Am J Roentgenol 176 1493-1498... 

Casarella W, Knowles D, Wollf M, et al (1978) Focal nodular hyperplasia and liver cell adenoma. AJR Am J Roentgenol 131 393-402... 

Welch TJ, Sheedy PF, Johnson CM, et al (1985) Focal nodular hyperplasia and hepatic adenoma comparison of angiography, CT, US and scintigraphy. Radiology 156 593-595... 

Focal nodular hyperplasia (FNH), similarly to hepatic adenoma, is a hypervascular and nonencap-sulated lesion that occurs predominantly in young women, who probably share a common predisposing factor of hepatic venous abnormality. FNH can be often distinguished fi-om adenoma by the absence of fat, calcification or hemorrhage, and by the presence of a central scar and marked hypervascularity (Choi and Freeny 1998 Ichikawa et al. 2000). Some... 

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