Possible Origin of Aldosteronoma from Adrenohepatic Fusion Resulting in Intrahepatic Tumor

doi:10.4236/oju.2013.36042

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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

Email: [email protected]

Received August 9, 2013; revised August 28, 2013; accepted September 3, 2013

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.

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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