1.INTRODUCTION
Cushing’s syndrome is a collection of metabolic disorders and signs
resulting from long-term excessive cortisol secretion by the adrenal
cortex. These include moon face, centripetal obesity, skin striae, acne,
hypertension, osteoporosis, and others. It is also known as
hypercortisolism[1], [2]. When the condition is caused by
pituitary tumor leading to excessive ACTH secretion, it is referred to
as Cushing’s disease. If ACTH-like substances secreted by malignant
tumors outside the pituitary and adrenal glands stimulate the adrenal
cortex to secrete glucocorticoids, it is called ectopic ACTH
syndrome[1]. In non-ACTH-dependent Cushing’s syndrome, cortisol can
be secreted not only by the adrenal glands autonomously but also by
ectopic adrenal tissue or ectopic adrenal adenomas with secretory
functions[1], [3]. In the case reported in this article,
cortisol was secreted by an ectopic adrenal adenoma located at the renal
hilum, leading to typical Cushing’s syndrome, which is rare in clinical
practice.
During embryonic development, the adrenal cortex arises from a group of
mesothelial cells between the root of the mesentery of the abdominal
wall and the urogenital ridge, while the adrenal medulla originates from
the sympathetic nervous system. During the migration of medullary cells
to the fetal adrenal cortex region, fragments of the adrenal cortex may
be split, and some fragments closely related to the urogenital ridge may
become ectopic with the migration of the developing gonads[4],
[5]. Ectopic adrenal tissue typically occurs in the following
locations: abdominal axis (32%), broad ligament (23%), epididymis
(7.5%), and spermatic cord (3.8%-9.3%)[6]. Case reports have
shown that 0.1%-6% of ectopic adrenal tissue occurs in the kidney,
primarily located beneath the capsule at the upper pole of the
kidney[6]. Most of the adrenal tumors arising from ectopic tissue
are non-functional[7], [8]. Interestingly, among reported cases
of functional ectopic adrenal adenomas, most tumors are located at the
renal hilum[3], [9]. Given the rarity of this condition and the
complex anatomical structure of the renal hilum, when typical clinical
manifestations of Cushing’s syndrome are present, but imaging studies
show no corresponding adrenal enlargement or nodular changes, and
hormone tests indicate non-ACTH-dependent hypercortisolism, the
possibility of ectopic adrenal cortisol-producing adenomas, particularly
at the abdominal axis and gonadal region, especially at the renal hilum,
should be considered. Additionally, the feasibility of tumor resection
in these complex anatomical regions should also be evaluated[7],
[8].
This report presents a case of an ectopic adrenocortical adenoma located
in the renal hilum that caused Cushing’s syndrome. In addition to
exhibiting typical signs of hypercortisolism and corroborative hormonal
test results, the ectopic adrenal adenoma was situated at the renal
hilum, in close association with the renal vein, making resection
challenging. Furthermore, the contralateral kidney was nonfunctional,
necessitating maximum preservation of nephron units during surgery. We
successfully performed complete tumor resection using robot-assisted
laparoscopy. A 4-month postoperative follow-up showed satisfactory
therapeutic outcomes. By sharing the diagnostic and therapeutic process,
along with follow-up results of this case, we aim to provide a reference
for the management of rare types of ectopic adrenal glands and to
explore the advantages of robot-assisted laparoscopic techniques in
complex tumor resections.