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.