以機器人腎上腺切除術治療之右腎上腺神經鞘瘤：一例模仿腺瘤且具間隔期生長的罕見偶發瘤個案

王惟弘、王彥傑

國泰綜合醫院 外科部 泌尿科

Right Adrenal Schwannoma Managed by Robotic Adrenalectomy: A Rare Case of Incidentaloma Mimicking Adrenal Adenoma with Interval Growth

Wei-Hung Wang, Yen-Chieh Wang

Division of Urology, Department of Surgery, Cathay General Hospital, Taipei, Taiwan

Abstract

We present a 43-year-old woman with chronic hepatitis B on medical treatment who presented with a suspected liver lesion on abdominal ultrasound during routine outpatient department (OPD) follow-up. Abdominal MRI revealed small liver cysts without a hypervascular tumor but showed a 1.5 cm mildly enhancing nodule in the right adrenal gland. Metabolic work-up confirmed a non-functioning tumor. The lesion was suspected to be a benign cortical adenoma, and active surveillance was advised. However, a one-year follow-up contrast-enhanced CT scan showed tumor growth to 2 cm with enhancement. The rapid growth raised concern for adrenal cortical carcinoma. Robot-assisted laparoscopic right adrenalectomy was subsequently performed. The gross appearance was a gray-white, elastic nodule. Pathology showed a schwannoma with spindle cells and wavy nuclei in the medulla. Immunohistochemical studies was positive for S100 and SOX10. Ki-67 was 2-3%. Synaptophysin showed no admixed ganglion cells. The patient recovered well and was discharged on the fourth postoperative day. No recurrence was noted on OPD follow-up.

Adrenal schwannomas are rare benign tumors arising from Schwann cells of the autonomic nerve fibers within the adrenal medulla. They are exceptionally uncommon, with only about 40 cases reported in the medical literature. Accounting for only 1-3% of all schwannomas and 0.2-0.5% of adrenal tumors, they often present as incidentalomas on imaging. Preoperative diagnosis is challenging due to non-specific imaging features, mimicking non-functioning adenomas or malignant lesions. As a result, surgical resection is needed for definitive histopathological confirmation. The clinical significance of adrenal schwannoma lies in its resemblance to more common adrenal pathologies. This highlight the need for vigilant surveillance of growing nodules. Standard management involves minimally invasive surgical excision, with excellent outcomes and low recurrence risk. However, long-term follow-up is recommended. In this report, we share our experience in diagnosing and managing this rare entity. We emphasize the role of multidisciplinary approaches, including advanced imaging and pathology. They guide effective patient care and prevent unnecessary interventions. Continued awareness and research are essential for accurate identification and optimal outcomes in such cases.