Adrenal cysts are a relatively uncommon disorder and most such cases are discovered at autopsy. According to the overseas cases, the reported incidence is 0.06~0.18% and the incidence is increasing due to the widespread use of ultrasonography and computed tomography scanning. Adrenal cysts are usually asymptomatic and they need to be differentiated from other cystic lesions including liver, pancreas and kidney cystic lesions. We report here on a case of a 39-year-old female with an adrenal pseudocyst that was misdiagnosed preoperatively as a pancreas mucinous cystic neoplasm.