Medicine® ®
OPEN
Intrahepatic adrenocortical adenoma arising from adrenohepatic fusion mimicking hepatic malignancy
Two case reports
Yong Soo Cho, MDª, Jin Woong Kim, MD, PhDa, Hyun Ju Seon, MD, PhDª, Ju-Yeon Cho, MD, PhDb, Jun-Hee Park, MD, PhD°, Hyung Joong Kim, PhDd, Yoo Duk Choi, MD, PhDe, Young Hoe Hur, MD, PhDf,*
Abstract
Rationale: Intrahepatic adrenocortical adenoma (IAA) arising from adrenohepatic fusion (AHF) is rare and its imaging findings are not well established. Moreover, it is easily misdiagnosed as malignant hepatic tumor in patients at risk of malignancy. Its key finding is the connection between the tumor and adrenal gland. When IAA from AHF is suspected, biopsy should be considered to avoid unnecessary surgery. Herein, we report 2 cases of IAA from AHF.
Patient concerns: A 59-year-old woman was admitted due to a 1.5-cm hypoechoic nodule in the right hepatic lobe detected on ultrasound for hepatocellular carcinoma (HCC) surveillance due to chronic hepatitis B. Contrast-enhanced computed tomography (CT) and gadoxetic acid-enhanced magnetic resonance imaging (MRI) were performed to evaluate the hepatic mass. Another 75- year-old woman was admitted due to rectal adenocarcinoma detected on colonoscopy. Contrast-enhanced CT depicted a 2.5-cm mass in the right hepatic lobe.
Diagnosis: In case 1, CT and MRI showed a 1.5-cm subcapsular mass in the right hepatic lobe with typical findings of HCC in a patient with chronic hepatitis B. The mass was confirmed as IAA from AHF after the laparoscopic surgery. In case 2, CT showed advanced rectal malignancy and a 2.5-cm poorly enhancing mass in the right hepatic lobe. The tentative diagnosis was hepatic metastasis. However, based on the connection between the tumor and adrenal gland during preoperative review, the presumed diagnosis was changed to IAA from AHF, which was confirmed on biopsy.
Interventions: The hepatic mass connected with the right adrenal gland was laparoscopically resected in case 1. Laparoscopic lower anterior resection for rectal malignancy and percutaneous biopsy for the hepatic mass were performed in case 2.
Outcomes: The first patient had an uneventful recovery, without recurrence on the 3-year follow-up CT. The second patient had an uneventful postoperative course and has been alive for 12 months postoperatively without pathologically proven IAA changes on follow-up CT.
Lessons: When hepatic mass is found adjacent to the right adrenal gland on imaging, the connection between the tumor and adrenal gland should be investigated. When IAA arising from AHF is suspected, biopsy should be considered to avoid unnecessary surgery.
Abbreviations: AHF = adrenohepatic fusion, CT = computed tomography, HCC = hepatocellular carcinoma, IAA = intrahepatic adrenocortical adenoma, MRI = magnetic resonance imaging.
Keywords: adrenohepatic fusion, biopsy, computed tomography, intrahepatic adrenocortical adenoma, magnetic resonance imaging
Editor: N/A.
Funding: This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (No. 2018R1D1A1B07046619).
Conflict of interest: Hyung Joong Kim has received research grants from the National Research Foundation of Korea (NRF) (No. 2018R1D1A1B07046619). Yong Soo Cho, Jin Woong Kim, Hyun Ju Seon, Ju-Yeon Cho, Jun-Hee Park, Yoo Duk Choi, and Young Hoe Hur declare that they have no conflict of interest.
ª Department of Radiology, Chosun University Hospital, Chosun University College of Medicine, Gwangju, Republic of Korea, b Department of Internal Medicine, Chosun University Hospital, Chosun University College of Medicine, Gwangju, Republic of Korea, “Department of Otolaryngology-Head and Neck Surgery, Chosun University
Hospital, Chosun University College of Medicine, Gwangju, Republic of Korea, ªImpedance Imaging Research Center, Kyung Hee University, Seoul, Republic of Korea,
e Department of Pathology, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Jeollanam-do, Republic of Korea,
Department of Hepato-Biliary-Pancreas Surgery, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, Jeollanam-do, Republic of Korea.
Correspondence: Young Hoe Hur, Department of Hepato-Biliary-Pancreas Surgery, Chonnam National University Hwasun Hospital, Chonnam National University Medical School, #322 Seoyang-ro, Hwasun-eup, Hwasun-gun, Jeollanam-do 58128, Republic of Korea (e-mail: surgihur@naver.com).
Copyright @ 2019 the Author(s). Published by Wolters Kluwer Health, Inc.
This is an open access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal.
Medicine (2019) 98:23(e15901)
1. Introduction
Intrahepatic adrenocortical adenoma (IAA) arising from adre- nohepatic fusion (AHF) is rare; however, it could mimic malignant hepatic tumor in patients at risk of malignancy. In patients at risk of primary malignancy, IAA arising from AHF is frequently misdiagnosed as primary hepatic malignancy such as hepatocellular carcinoma (HCC) because of its rarity and the lack of well-established imaging findings.[1-3] In patients at risk of metastatic hepatic tumor, unnecessary surgery or chemotherapy could be performed or patients could lose the chance of curative surgery due to misdiagnosed metastasis of IAA arising from AHF. We experienced 2 cases in which the connection between the tumor and right adrenal gland could be a key imaging finding and percutaneous core needle biopsy was helpful for confirmative diagnosis. Therefore, we report 2 cases with review of the previous literature.
2. Case report
2.1. Case 1
A 59-year-old woman was admitted for the evaluation of a 1.5- cm hypoechoic subcapsular nodule in the right hepatic lobe detected during the ultrasound screening examination for HCC
surveillance due to chronic hepatitis B. Physical examination revealed no characteristic features. Laboratory tests upon admission showed her serum was positive for hepatitis B core antigen and hepatitis B surface antigen, but negative for hepatitis B surface and hepatitis C virus antibodies. Other laboratory values including aspartate aminotransferase, alanine aminotrans- ferase, total bilirubin, alkaline phosphatase, and alpha-fetopro- tein were unremarkable.
She underwent dynamic contrast-enhanced computed tomog- raphy (CT) to evaluate the right hepatic mass. CT images showed a 1.5-cm subcapsular round mass with hyper-arterial enhance- ment and delayed washout in the posterior segment at the right hepatic lobe, which was suspected as HCC (Fig. 1A). In order to distinguish the tumor between the HCC and other hepatic tumors, gadoxetic acid-enhanced liver magnetic resonance imaging (MRI) was performed, which also depicted a 1.5-cm well-demarcated round subcapsular mass with typical imaging findings of HCC such as hyper-arterial enhancement, delayed washout, and hypointensity on hepatobiliary phase on gadoxetic acid-enhanced MR images (Fig. 1B and C). The tumor was diagnosed as a HCC based on the typical findings seen on dynamic contrast-enhanced CT and gadoxetic acid-enhanced MRI and the history of chronic hepatitis B in accordance with the American Association for the Study of Liver Diseases (AASLD)
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guideline.[4] According to AASLD guideline, laparoscopic right posterior sectionectomy was decided by a multidisciplinary tumor board consisting of hepatologists, hepatic surgeons, oncologists, and abdominal radiologists at our hospital. Although the tumor was not depicted as a lesion with hot uptake on 18F-FDG-PET/CT image (Fig. 1D), presumed diagno- sis was HCC because the patient had chronic hepatitis B, which is high risk for HCC.
In the operative field, the surgeon identified a 1.5-cm well- circumscribed, capsulated white-to-yellow hepatic mass that was connected with the right adrenal gland. The cut surface of the tumor was yellowish and showed signs of fat component (Fig. 1E). IAA arising from AHF was pathologically confirmed by laparoscopic surgical resection and microscopic findings. The patient had an uneventful recovery and was discharged on postoperative day 7. No tumor recurrence in the liver was noted on the 3-year follow-up CT.
2.2. Case 2
A 75-year-old woman was admitted due to a rectal nonmucinous adenocarcinoma detected on colonoscopy during a medical screening program. Her history was otherwise noncontributory.
A physical examination revealed no characteristic features. Laboratory tests upon admission were unremarkable. She underwent abdominal dynamic contrast-enhanced CT for staging of the rectal malignancy, which showed advanced upper rectal malignancy with perirectal invasion and regional lymph- adenopathies. A 2.5-cm lobulated well-defined poorly enhancing subcapsular mass in the posterior segment of the right hepatic lobe was also detected on CT images (Fig. 2A and B). The hepatic tumor was tentatively diagnosed as a solitary hepatic metastasis from rectal malignancy at the time of the staging. However, a connection between the hepatic tumor and right adrenal gland was found on the coronal CT image during careful review by a multidisciplinary tumor board for appropriate treatment plan (Fig. 2C). This imaging finding is considered as a key factor to diagnose IAA arising from AHF, although its incidence is rare and its imaging findings are not well established. Thus, percutaneous ultrasound-guided core needle biopsy was per- formed to distinguish between hepatic metastasis and IAA arising from AHF (Fig. 2D). The results of immunohistochemical staining for the obtained tumor tissue were negative for hepatocyte-specific antigen and positive for melan-A and alpha-inhibin, and the tumor was pathologically confirmed as IAA arising from AHF (Fig. 2E).
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She underwent laparoscopic lower anterior resection with loop ileostomy for rectal malignancy and adjuvant chemotherapy using oxaliplatin and 5-fluorouracil. She had an uneventful postoperative course and has been alive for 12 months postoperatively. The pathologically proven adrenocortical ade- noma arising from AHF showed no changes on follow-up CT images.
3. Methods
The patients provided signed, informed consent for publication of the cases, and the study was approved by the Institutional Review Board of Chonnam National University Hwasun Hospital (CNUHH-2019-068).
4. Discussion
AHF is known as the union between the right adrenal gland and liver by intermingling its parenchyma. Honma reported that AHF was found in 63 of 636 unselected autopsies (9.9%), suggesting that this was a rather common anatomic condition. Moreover, older age groups had a higher incidence of AHF.[5] Adrenocorti- cal adenoma from AHF is now more commonly detected in the clinical practice than what was known because imaging techniques such as CT and MR have been developed and increasingly used. However, adrenocortical adenomas in the liver have been rarely encountered. Most of the reported cases were adrenal rest tumors, that is, adrenal cortical tumors originated from the accessory adrenal tissue in the liver with intact adrenal glands in their normal position.[6-8] Because IAA arising from AHF is rare, the clinical presentation and imaging findings of the tumor have been rarely described in the literature. Most IAAs have been detected incidentally during imaging work-up, especially in patients with known malignancy.
Adrenocortical adenoma is highly suggested when the HU measurement is less than 10 on unenhanced CT.[9,10] This characteristic imaging feature is based on the presence of intralesional fat. Typical adrenocortical adenoma was demon- strated as early enhancement on the arterial phase and delayed washout pattern on far delayed phase images. For these reasons, the IAA arising from AHF can mimic HCC on cross-sectional imaging.[11] In previous reports, most adenoma cases from AHF were preoperatively misdiagnosed as primary or metastatic hepatic tumors, especially HCC.[1-3,12,13] As mentioned, imaging findings of IAA from AHF tend to mimic those of HCC, making its differentiation very difficult in patients highly at risk for HCC. That is why most of the reported cases and our first case were misdiagnosed as HCC. In case 1, the subcapsular hepatic mass was preoperatively misdiagnosed as HCC due to chronic hepatitis B history and typical enhancement pattern of HCC on CT and MRI. However, low 18F-FDG uptake within the tumor similar to the liver parenchyma and low value of alpha- fetoprotein suggest low likelihood of HCC. Moreover, because the imaging finding of IAA from AHF has not been well established, the connection between the tumor and right adrenal gland was not considered, which implies the tumor arising from AHF. In case 2, a subcapsular hepatic mass was initially diagnosed as a single hepatic metastasis due to the preexisting rectal malignancy and poorly enhancing hepatic mass on CT. However, the connection between the tumor and right adrenal gland attracted our attention in the preoperative imaging reviews.
Thus, we considered the possibility of IAA from AHF and performed US-guided core needle biopsy to confirm our diagnosis. Similar with our 2 cases, a hepatic mass is demonstrated adjacent to the right adrenal gland on the cross- sectional imaging, the possible connection between the tumor and adrenal gland should be carefully investigated using multiplanar reconstruction cross-sectional images, which could be a key finding for correct diagnosis.
Accurate diagnosis of IAA arising from AHF is important for pathologic confirmation as well as for preoperative diagnosis. Pathologically differentiating IAA in AHF from HCC is difficult without clinical suspicion of IAA, due to their similar histological findings.[3,7] Immunohistochemical staining using hepatocyte- specific antigen, melan-A, or alpha-inhibin is useful to differenti- ate IAA from HCC. Immunohistochemical staining of IAA is generally negative for hepatocyte-specific antigen and positive for melan-A or alpha-inhibin and that of HCC is contrary to the results of IAA.[7]
Although the imaging findings of IAA in AHF are similar to those of primary or metastatic hepatic tumors, the connection between the tumor and right adrenal gland could be a key finding for accurate diagnosis. Moreover, low 18F-FDG uptake on PET/ CT could help diagnose IAA arising from AHF. When IAA arising from AHF is suspected on imaging, percutaneous core needle biopsy should be considered. In addition, the obtained specimen should be evaluated for the possibility of IAA arising from AHF in order to avoid unnecessary surgery.
Author contributions
Conceptualization: Jin Woong Kim, Young Hoe Hur.
Data curation: Ju-Yeon Cho, Yoo Duk Choi.
Funding acquisition: Hyung Joong Kim.
Supervision: Jin Woong Kim, Jun-Hee Park, Young Hoe Hur. Writing - original draft: Yong Soo Cho.
Writing - review & editing: Jin Woong Kim, Hyun Ju Seon, Jun-
Hee Park, Hyung Joong Kim, Young Hoe Hur.
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