Giant adrenal pseudocyst with unclear preoperative origin: a case report and literature review.

Introduction: Adrenal cysts are relatively rare, and most are nonfunctional and lack specific clinical manifestations, often being discovered incidentally during imaging examinations. For giant adrenal cysts with a maximum diameter exceeding 10 cm, especially when accompanied by degenerative changes such as hemorrhage, fibrosis, and calcification, compression of adjacent organs and obscuration of anatomical planes may increase the difficulty of determining the origin preoperatively, and they may even be misdiagnosed as pancreatic, renal, or other retroperitoneal cystic lesions. This article reports one case of a giant adrenal pseudocyst with unclear origin before surgery and discusses its diagnostic and surgical management strategies. Case report: A 36-year-old woman was admitted after a left retroperitoneal mass was incidentally discovered during trauma evaluation one month earlier. Contrast-enhanced CT showed a cystic low-density lesion measuring approximately 108 mm × 102 mm × 108 mm in the left retroperitoneal space, with marginal calcification. The left adrenal gland was not distinctly identified, and the lesion was closely related to the stomach, spleen, and pancreas. The organ of origin remained uncertain preoperatively, with cystic lesions of adrenal, pancreatic, or gastric origin considered in the differential diagnosis. After multidisciplinary discussion, laparoscopic resection was performed. Intraoperatively, the lesion was densely adherent to surrounding organs and its origin was difficult to determine; resection was completed after decompression, and the residual cyst wall on the splenic side was treated with electrocautery. Postoperative pathology confirmed a left adrenal pseudocyst with calcification. The patient recovered smoothly, and no complications were observed during follow-up. Conclusion: Giant complex adrenal pseudocysts may mimic other left retroperitoneal cystic lesions, and the diagnostic difficulty lies in determining the organ of origin. For giant retroperitoneal cystic lesions of unclear origin, adrenal origin should be included as an important differential diagnosis, and comprehensive decisions should be made based on imaging, endocrine evaluation, and multidisciplinary discussion; if no safe dissection plane exists intraoperatively, individualized management should be implemented.