Focal nodular hyperplasia of the liver in children should suggest an endocrine illness

Background: Focal nodular hyperplasia (FNH) is the second most common benign liver tumour after liver haemangiomas and it is most often found in females between the ages of 30 and 50 under oral contraceptives. In children, FNH represents 2% of the primary tumors of the liver. Case Report: A 12-year-old girl with a previous ultrasonographic diagnosis of hepatic steatosis was admitted for evaluation of right abdominal pain. Physical examination showed obesity, hirsutism and acne in absence of clinical signs of liver disease. Menarche occurred at the age of 9 years and her cycles were irregular for oligomenorrhea and menorrhagia. She was not under treatment with oral contraceptives. Liver function tests were within the normal ranges. Abdominal ultrasonography showed a hypoechoic, 30×24×28 mm, well-defined mass in V segment of the liver with a central scar. Abdominal contrast magnetic resonance and ultrasonography imaging confirmed the diagnosis of FNH. Alphafetoprotein, carcinoembryonic antigen, Ca-19-9 and Ca-125 were negative. A brain CT-scan and an electroencephalography did not show abnormal findings. Thyroid profile and sexual hormones were in the range of normality. Pelvic ultrasonography showed ovaries with sizes at the high range of normality in the absence of cysts. Due to an episode of hypoglycaemia (glucose: 45 mg/dl) which occurred two hours after dinner, she performed a metabolic screening (negative) and evaluation of serum levels of GH (0.09 ng/ml, normal), insulin (37.8 mU/ml, high), and cortisol (47 ng/ml, low). Oral glucose tolerance test indicated a normal tolerance to glucose with hyperinsulinism. 17-OHP values after ACTH stimulation test suggested a status of carrier of heterozygous mutation of 21- hydroxylase deficiency (late onset form). Conclusions: Although in the described patient a definite causal relationship between heterozygous carrier state for 21-hydroxylase deficiency (late onset form), hyperinsulinism and FNH was not clearly documented, our case report suggests that in children with diagnosis of FNH is desirable to investigate for an endocrine disorder. This recommendation is further supported not only by the well known association of FNH with long-term use of oral contraceptives, but also in some cases with diabetes mellitus.