a 45-year - old man suffering from heavy alcoholism underwent an abdominal ultrasonography ( us ) during a routine check - up . on a transverse abdominal us image , echogenicity of the liver was diffusely increased , suggesting fatty infiltration in the liver . in addition , an approximately 2.7 cm low - echoic lesion was found in segment vii of the liver ( fig . for further evaluation , a dynamic contrast - enhanced liver ct was recommended . on a precontrast scan , a 2.5 cm well - demarcated , low - attenuating nodule was seen in the subcapsular area of hepatic segment vii ( fig . after contrast administration , the lesion showed heterogeneous enhancement on arterial and portal phase images and washout on delayed phase images ( mean hu : -5 on precontrast phase , 27 on arterial , 89 on portal , and 46 on delayed phase ) ( fig . the level of alpha - fetoprotein was also normal ( 1.8 ng / ml ) . the tentative diagnosis at the time of interpretation included hcc with fatty metamorphosis , hepatic adenoma , and angiomyolipoma . a liver mri with gd - eob - dtpa was performed for further characterization of the lesion . on in- and opposed - phase t1-weighted gradient recalled echo images , a marked signal drop of the lesion , as well as of the liver was noted , suggestive of an abundant fatty component within the lesion and the background liver ( fig . after gd - eob - dtpa administration , the lesion showed modest arterial enhancement on the arterial phase , and a washout pattern on the portal and equilibrium ( 3 minutes ) phase images ( fig . hepatobiliary phase images obtained 20 minutes after contrast injection demonstrated a clear defect of the lesion compared to the hyperintense background liver . a coronal multi - planar reformatted image obtained 15 minutes after contrast injection clearly depicts a relationship between the lesion and the right adrenal gland ( fig . even though the hyperintense focus seen on hepatobiliary phase may occur due to the nonspecific retention of gadolinium , it also may indicate the possibility of hepatocyte - specific contrast uptake by the tumor ( fig . however , according to american association for the study of liver diseases ( aasld ) guidelines ( 8) , a biopsy should be the next step for diagnosis due to the patient 's non - cirrhotic liver , normal level of alpha - fetoprotein , and atypical vascular pattern on ct . therefore , a biopsy was performed . however , the pathologic diagnosis was epithelial cell neoplasm with clear cytoplasm and was not conclusive with a differential list of hcc , adrenal adenoma , and renal cell carcinoma . in addition to the patient 's history of chronic alcohol abuse , the enhancement pattern of the lesion on mr dynamic images , and the possibility of hepatocyte - specific contrast uptake by the tumor , can not completely exclude the diagnosis of hcc with fatty metamorphosis . the lesion was found to be located within the liver and was completely covered with the hepatic capsule . the right adrenal gland was slightly attached to the hepatic capsule ; however , dissection between the liver and adrenal gland was easily performed . a microscopic examination showed that the nodule was well encapsulated and completely surrounded by hepatocytes , hence confirming its intrahepatic location ( fig . the tumor was confirmed as an adrenal cortical adenoma consisting of clear cells with abundant cytoplasm ( fig . a retrospective microscopic examination demonstrated that dilated vessels and an inner organizing hematoma with vascular proliferation off - center of the lesion corresponded to the area showing focal contrast uptake at 20 minute delayed mr images ( fig . the final pathologic diagnosis was an adrenal cortical adenoma arising from ectopic adrenal tissue in the liver . adrenal cortical adenoma is the most common benign neoplasm in the adrenal gland and treatment is usually not necessary unless it is symptomatic . approximately 80% of adrenal adenomas show < 10 hu on an unenhanced ct and can be easily diagnosed as a lipid - rich adenoma without other sophisticated examinations ( 9 ) . even though adrenal adenoma has little or no fatty component , also known as a lipid - poor adenoma , it can be differentiated from non - adenomatous lesions through the calculation of the percentage enhancement washout with high sensitivity and specificity ( 9 ) . according to caoili et al . ( 9 ) , the use of the percentage enhancement washout threshold of 60% allowed them to correctly diagnose 19 of 22 lipid - poor adenomas with 98% sensitivity and 92% specificity . in our case , even though the patient underwent the liver protocol ct , which contains unenhanced , arterial phase , portal phase , and equilibrium ( 3 minutes ) phase , we were able to obtain 60% enhancement washout of the lesion . had we calculated the percentage enhancement washout using 15 minute delayed phase ct images which are usually recommended for the characterization of adrenal lesions , the percentage might have been much greater than 60% . therefore , if the lesion in our patient had been located at the right adrenal gland , the correct diagnosis could have easily been achieved due to its lipid - rich character and its high enhancement washout of greater than 60% . however , like in our case , adrenal adenomas arising from a heterotopic or ectopic gland can result in diagnostic dilemmas . it is important to diagnose ectopic adrenal tissue or its neoplasm as noninvasively as possible , as they are usually asymptomatic and no treatment is necessary . however , there are three circumstances in which clinical problems may occur : first , ectopic adrenal tissue may become symptomatic if it produces hormones such as aldosterone , cortisol , or androgens , which can lead to the presentation of cushing 's syndrome , aldosteronoma , conn 's syndrome or extreme virilization ( 10 - 12 ) . second , various kinds of neoplasms such as neuroblastoma , myelolipoma , adenoma , and oncocytoma may occur in ectopic adrenal tissue ( 10 , 13 , 14 ) . third , the ectopic adrenal tissue itself or abnormality in the ectopic tissue may mimic lymphadenopathy or tumors in other abdominal organs ( 6 ) . . however , in our case , even if we could consider the unique location of the lesion ( bare area of segment vii ) and proximity of the lesion to the right adrenal gland at the time of interpretation , complete exclusion of the possibility of hepatic tumor , in particular , hepatic adenoma or carcinoma , would be difficult due to the patient 's history of chronic alcohol abuse and a similar dynamic enhancement pattern of the lesion to hepatocellular adenoma or carcinoma . furthermore , hyperintense focus within the lesion on 20-minute delayed mr hepatobiliary phase images led to greater confusion . when we retrospectively analyzed the microscopic slides of the lesion with our abdominal pathologist , there were dilated vessels and inner organizing hematoma with vascular proliferation off - center of the lesion , which corresponded to the area showing focal hyperintensity at 20-minutes delayed mr images . considering the microscopic findings , the hyperintense area seen on the 20-minute delayed hepatobiliary phase images might be due to prolonged retention of the gadolinium component by dilated tumoral vasculature , and not due to the true uptake of eob - dtpa by hepatocytes . even though there were several reports on adrenal adenoma in adrenohepatic fusion tissue ( 6 , 7 ) , our case is the first radiologic demonstration of adenoma arising from an ectopic adrenal gland in the liver . the tumor closely abutted the right adrenal gland on both the radiologic examination and the operative field . however , the microscopic finding revealed that the tumor was well encapsulated and completely surrounded by hepatic parenchyma , confirming its pure intrahepatic and ectopic location . despite of the difficulties in reaching the correct preoperative diagnosis of adenoma originating from an ectopic or heterotopic adrenal gland , close proximity of the lesion to the adrenal gland might provide radiologists with a clue for this potential occurrence , thereby possibly averting aggressive surgery such as a right posterior sectionectomy .
we report a case of an adenoma arising from an ectopic adrenal gland mimicking a hepatocellular carcinoma in a heavy alcohol abuser . 
 a mdct showed a 2.7 low - attenuating nodule in segment vii of the liver through all ct phases . 
 compared to a precontrast image , however , a subtle enhancement was noted on the arterial phase ct image . 
 on t1 weighted in- and opposed - phase mr images , an abundant fat component within the lesion was seen . 
 dynamic contrast - enhanced mr images after administration of gadolinium ethoxybenzyl diethylenetriaminepentaacetic acid ( gd - eob - dtpa ) more clearly depicted hypervascularity and wash - out of the lesion on arterial and portal phases , respectively . on delayed hepatobiliary phase mr images , 
 obtained 20 minutes after gd - eob - dtpa administration , subtle uptake or retention of the contrast agent by the lesion was suspected . 
 a tumorectomy was performed and adrenal adenoma from an ectopic adrenal gland within the liver was confirmed .