Cystic adrenal lesions are very rare. There are no agreed upon published guidelines in terms of surgical or surveillance management. Malignancy has been rarely reported within cystic adrenal lesions. We present a case of a 73-year-old male with a large solitary adrenal cystic lesion.

This patient was referred to urology for evaluation of an adrenal mass. He had a medical history of hyperlipidemia, hypertension, peripheral vascular disease, depression and anxiety. He also underwent wide local excision in 2015 (with negative surgical margins) for pT1a, cN0M0 Grade 1 stage I leiomyosarcoma of the left thigh. Adjuvant therapy was not recommended. He failed to undergo surveillance imaging until January 2020. Computerized tomography (CT) chest abdomen and pelvis with IV contrast early January 2020 showed a 5.5 cm centrally hypodense left adrenal mass with hyperdensity peripherally (fig. 1). The right adrenal gland was unremarkable. For further characterization, a CT with and without contrast was obtained (fig. 2). This showed a 4.7 × 4.8 × 5.2 cm left adrenal mass demonstrating peripheral enhancement and an indeterminate washout (absolute washout 55.6%, relative washout 21.7%). Fluorodeoxyglucose-positron emission tomography CT was negative.

Figure 1. CT abdomen and pelvis with intravascular contrast showing incidental cystic heterogeneous left adrenal mass with calcifications: a, coronal view; and b, axial view.

Figure 2. Adrenal mass protocol CT (with and without contrast) again demonstrating heterogenous left adrenal mass with indeterminate washout: a, coronal view; and b, axial view.

The patient had longstanding panic attacks and generalized anxiety with no palpitations or skin changes. Functional workup including a 1 mg dexamethasone suppression test, plasma metanephrines, aldosterone-to-renin ratio and serum DHEAS were all negative. Percutaneous biopsy of the mass with interventional radiology showed benign adrenal components with bland necrosis. Due to the false negative rate of biopsy surveillance of the adrenal lesion was continued. Magnetic resonance imaging 6 months later showed slight enlargement of the mass, now measuring 5.5 × 5.1 × 5.9 cm with enhancement (fig. 3). Additionally, the solid component of this mass appeared larger and more complex. His case was presented at tumor board, with recommendations to obtain a chest CT to rule out a rapidly enlarging lung mass, as there was a previously noted 2 mm lung nodule, and to proceed with adrenalectomy if negative. Chest CT showed no metastatic disease and he elected to proceed with robot-assisted laparoscopic left adrenalectomy. He underwent uncomplicated robot-assisted laparoscopic left adrenalectomy. He recovered well postoperatively and was discharged on postoperative day 1. His pathology showed benign adrenal gland with central organizing clot, measuring 6.5 cm in greatest dimension.

Figure 3. Magnetic resonance imaging June 2021 showing T2 weighted Turbo Spin Echo (TSE) sequences demonstrating interval growth and irregular components of left adrenal mass: a, coronal view; and b, axial view.

While hemorrhage can cause enlargement on interval imaging, enlarging solid adrenal lesions, particularly those >5 cm in size, are generally considered malignant until proven otherwise. Additionally, while the proportion of malignant lesions by size varies widely in the literature, there is general consensus that lesions >4 cm without benign features have a high risk of malignancy. The American College of Radiology Incidental Findings Committee recommends consideration of resection of masses >4 cm due to this risk, as do guidelines from the Canadian Urological Association.^1,2 Cystic adrenal lesions are rare in comparison and the relative risk of malignancy is unknown. As such, management of cystic adrenal lesions remains controversial. If we extrapolate from the literature regarding complex renal lesions the internal complexity of the lesion would be of greater concern than the overall size.³ This lesion did exhibit significant internal complexity and a general increase in this internal complexity over time but was ultimately a benign entity. Acute adrenal hemorrhage has an intermediate or high T1 signal intensity, while chronic has a low intensity T1 appearance and either low or high T2.⁴ This patient’s adrenal lesion did have an area of high T2 intensity, but as this is a nonspecific finding, it would be difficult to characterize his mass as a benign entity with hemorrhage based on imaging alone. Further research involving multicenter collaboration with this rare entity will need to be undertaken with both radiology review and pathological correlation in order to fully understand rates of malignancy and thus need for active treatment and/or ongoing surveillance.