Open Journal of Urology, 2013, 3, 223-226
http://dx.doi.org/10.4236/oju.2013.36042 Published Online October 2013 (http://www.scirp.org/journal/oju)
Possible Origin of Aldosteronoma from Adrenohepatic
Fusion Resulting in Intrahepatic Tumor*
Takumi Takeuchi1, Takashi Inoue2, Keiko Kanemoto2, Kazuchika Hagiwara3, Koji Mikami1,
Mami Hattori1, Masayoshi Zaitsu1, Akiko Tonooka4, Toshimasa Uekusa4, Susumu Uda2
1Department of Urology, Kanto Rosai Hospital, Kawasaki, Japan
2Nephrology, Kanto Rosai Hospital, Kawasaki, Japan
3Diagnostic Radiology, Kanto Rosai Hospital, Kawasaki, Japan
4Pathology, Kanto Rosai Hospital, Kawasaki, Japan
Received August 9, 2013; revised August 28, 2013; accepted September 3, 2013
Copyright © 2013 Takumi Takeuchi et al. This is an open access article distributed under the Creative Commons Attribution License,
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
ABSTRACT
A 69-year-old woman was diagnosed with primary aldosteronism. An enhanced computed tomography (CT) scan be-
fore surgery indicated a right adrenal tumor outside the liver. Venous sampling tests revealed unilateral overproduction
of aldosterone by the right adrenal gland. Separation of the right adrenal cortex from the liver parenchyma was imprac-
tical during a laparoscopic right adrenalectomy because of the solid attachment between the two. Therefore, the exis-
tence of adrenohepatic fusion was determined. An incision was made within the right adrenal gland, leaving completely
the intrahepatic adrenal tissue on the inner side of the liver, because a partial hepatectomy was not preoperatively
planned, and the patient was not informed of the consent before the surgery. Pathological examination did not reveal
macro- or micro-adenomas in the resected right adrenal tissue. Aldosterone to renin ratio was as high as 1380 at 22 days
following the surgery. Therefore, aldosteronoma originated from the adrenohepatic fusion that remained on the inner
side of the liver was highly suspected. The patient’s blood pressure was well controlled, and she did not prefer hepatec-
tomy to be further performed, and therefore, medical therapy was continued. When planning the type of surgery
(laparoscopic or open) in these potentially confusing cases, it might be necessary to consider a possibility of the unex-
pected intraoperative diagnosis and the immediate measures to be performed based on the diagnosis.
Keywords: Adrenal; Tumor; Adrenohepatic Fusion
1. Introduction
Primary aldosteronism is more frequent than previously
speculated and it results in damaging the heart, blood
vessels, and kidneys [1]. Majority of the hypertensive
patients with primary aldosteronism, characterized by an
autonomous secretion of aldosterone from the aldoster-
onoma, are diagnosed with the introduction of advanced
imaging, such as computed tomography (CT) scans, mag-
netic resonance imaging (MRI), and ultrasound, as well
as sophisticated advancements in endocrinology tests. Pri-
mary aldosteronism among hypertensive patients is de-
termined by the aldosterone to renin ratio, and then con-
firmed by four testing procedures: oral sodium loading,
saline infusion, fludrocortisone suppression, and capto-
pril challenge. Furthermore, the laterality of aldosterono-
mas is determined by interventional venous sampling
techniques [2,3].
Those patients recently undergo laparoscopic adrena-
lectomy for antihypertensive drugs to be discontinued or
reduced and for the vital organs such as the brain, heart,
kidneys, and vessels to be protected from further damages
[4]. Here, we present a case of primary aldosteronism,
where adrenohepatic fusion was identified during a laparo-
scopic right adrenalectomy, and the aldosteronoma was
speculated to be originated from adrenohepatic fusion.
2. Case Report
A 69-year-old woman was diagnosed with primary al-
dosteronism using endocrinology evaluation, following
the cessation of antihypertensive drugs. The patient’s se-
rum potassium level was 3.1 mEq/L, and the aldosterone
to renin ratio was 406. After captopril challenge, the al-
dosterone to renin ratio was 249 (positive if >200) con-
*The authors declared no conflicts of interest.
C
opyright © 2013 SciRes. OJU

T. TAKEUCHI ET AL.
224
firming autonomous aldosterone production; however, after
saline infusion, the plasma aldosterone concentration was
52.8 pg/mL (positive if >60). Venous sampling tests re-
vealed unilateral overproduction of aldosterone by the
right adrenal gland (Table 1).
During the first hospital visit before nine years, the pa-
tient had hypertension with hypokalemia (2.8 mEq/L)
and a high aldosterone to renin ratio (>200). Thereafter,
hypertension and hypokalemia had been well controlled
with the administration of angiotensin converting enzyme
inhibitor combined with angiotensin receptor blocker. The
patient suffered a cerebral infarction before a year.
An enhanced CT scan before the surgery revealed a
right adrenal tumor responsible for the endocrine disor-
der located outside the liver; furthermore, liver cysts of
various sizes were observed (Figure 1). A small liver
cyst adjacent to the right adrenal mass altered the appro-
priate radiological diagnosis, because it displaced the ad-
renal mass located on the lateral inner side of the liver,
and resembled an extrahepatic mass.
Finally, a laparoscopic right adrenalectomy was planned.
The right adrenal vein branching from the inferior vena
cava was identified and resected. During the surgery, the
right adrenal cortex was solidly attached to the liver pa-
renchyma, and separating the two that determined the
existence of adrenohepatic fusion became impractical
(Figure 2(a)). An incision was made within the right
adrenal gland, leaving completely the intrahepatic adre-
nal tissue on the inner side of the liver (Figure 2(b)),
because partial hepatectomy was not preoperatively
planned and the patient was not informed of the consent
related to the surgical procedure. In addition, the possi-
bility remained that macro- or micro-adenomas existed in
the resected right adrenal tissue (Figure 3). Postoperative
course was uneventful.
Pathological examination did not reveal macro- or even
micro-adenomas in the resected right adrenal tissue. Al-
dosterone to renin ratio was as high as 1380 at 22 days
following the surgery, while serum potassium level was
normalized to 4.5 mEq/l, without the administration of
eplerenone. Therefore, it was highly suspected that the
aldosteronoma originated from the adrenohepatic fusion
remained on the inner side of the liver.
3. Discussion
Adrenohepatic fusion is reported as the fusion of adrenal
gland with liver, caused by the mesenchymal defect lead-
ing to the retardation of capsule formation with paren-
chymal mixing and the failure of local differentiation
into fetal and later adult fat cells [5]. Consequently, no
physical separation between the liver and the adrenal
gland was noticeable. Furthermore, it is observed in non-
human mammals [6,7].
Adrenohepatic fusion can be a hematogenous route of
right adrenal metastasis from hepatocellular carcinoma
[8-10]. Cortical adenomas arising in adrenohepatic fusion
are difficult to distinguish from primary hepatic tumors
using CT scans [11,12]; therefore, partial hepatectomy is
often performed with the diagnosis of a malignant hepa-
tocellular carcinoma. The location of adrenal ectopic or
rest tissue can occur anywhere along the course of go-
nadal descent during embryogenesis. This essentially
harmless tissue becomes hyperplastic or even tumorous
in patients with primary or secondary adrenal pathology.
For example, patients with congenital adrenal hyperpla-
Table 1. Venous sampling data.
Before ACTH loading Rt. adrenal vein Lt. adrenal vein IVC
PAC 586 54.1 39.4
C 14.3 19.8 10.4
AV/IVC cortisol ratio 1.3 1.9
PAC/C ratio 41.0 2.73 3.79
PAC/C lateralization ratio 15.0
After ACTH loading Rt. adrenal vein Lt. adrenal vein IVC
PAC 19,100 1620 298
C 304 463 21.8
AV/IVC cortisol ratio 13.9 21.2
PAC/C ratio 62.8 3.49 13.6
PAC/C lateralization ratio 18.0
Rt.: Right, Lt.: Left, PAC: plasma aldosterone concentration (pg/mL), C: cortisol (μg/dL), IVC: inferior vena cava, AV: adrenal vein, PAC/C lateralization ratio:
PAC/C in the right adrenal vein divided by PAC/C in the left adrenal vein, ACTH: adrenocorticotropic hormone, and after ACTH loading: sampling 25 minutes
after bolus intravenous injection of 0.25 mg of ACTH.

T. TAKEUCHI ET AL. 225
Figure 1. An enhanced computed tomography (CT) scan
reveals a right adrenal tumor on the inner side of the liver
(arrow), possibly originating from the adrenohepatic fusion.
(a)
(b)
Figure 2. (a) The right adrenal gland was solidly attached to
the liver. L: liver and Ad: right adrenal; (b) The right ad-
renal gland outside the liver was resected leaving the a dre no-
hepatic fusion tissue inside the liver. L: liver.
sia might present with an adrenocorticotropic hormone
(ACTH)-stimulated soft-tissue mass originating from the
adrenal rest, particularly in the gonads and retroperito-
neum [13]. Functioning and non-functioning adrenal rest
tumors of the liver are rarely reported and furthermore,
Figure 3. Hematoxylin-eosin staining of the resected adre-
nal gland, with no adenomas in the tissue.
these tumors are difficult to distinguish from the hepato-
cellular carcinomas located at the periphery of right he-
patic lobe [14-18].
The present case might be a right adrenal tumor origi-
nating from the adrenohepatic fusion and cannot be an
adrenal rest tumor because the right adrenal gland was
not surgically separated from the hepatic parenchyma. In
addition, venous sampling from the right adrenal vein
revealed elevated aldosterone levels. If the tumor was an
adrenal rest tumor that should be isolated from the right
adrenal tissue by definition, separating the right adrenal
cortex from the liver would have been possible. More-
over, preoperative elevated aldosterone levels would have
been detected in the hepatic veins instead of its detection
in the right adrenal vein.
Partial hepatectomy might be necessary to surgically
treat primary aldosteronism in this patient. However, her
blood pressure was well controlled by medical therapy,
and she did not prefer hepatectomy to be further performed.
Therefore, the medical therapy was continued. However,
in this case, it seemed difficult to appropriately diagnose
an adrenal tumor originating from the adrenohepatic fu-
sion. It could be diagnosed as a hepatic tumor in some
cases and an extrahepatic right adrenal tumor in others.
When laparoscopic or open surgery is planned in these

T. TAKEUCHI ET AL.
226
potentially confusing cases, it might be necessary to con-
sider a possibility of the unexpected intraoperative diag-
nosis and the immediate measures to be performed based
on the diagnosis. According to the medical databases,
there are no previous cases of patients where intrahepatic
adrenal tumors originating from the adrenohepatic fusion
were identified during the laparoscopic or open surgery.
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