Unusual Case of Adrenal Artery Aneurysm: Diagnosis and Management

•Adrenal mass workup•Differential diagnosis of presumed pheochromocytoma•Management of rare adrenal pathologies•Principles of endocrine surgery This vignette demonstrates the importance of thorough multidisciplinary evaluation for adrenal masses including clinical presentation, biochemical workup, and imaging modalities. Additionally, we demonstrate the necessity of considering differential diagnoses when working of pheochromocytomas and expanding the differential when the presentation is challenging. A 74-year-old man presents to the endocrinology clinic for follow up of a right adrenal mass found incidentally during cross-sectional imaging prompted by liver ultrasonography for cirrhosis surveillance. Further questioning revealed occasional headaches, anxiety, intermittent palpitations, and hypertension on two oral antihypertensives. On review of imaging, the mass was noted to be heterogenous with early arterial enhancement and had enlarged from 1.6 cm to 3.1 cm over the preceding three years (Figure 1). Biochemical testing demonstrated persistently elevated 24-hour urine normetanephrine on serial testing (801-804 mcg/24h [reference 122-676 mcg/24h]). Fractionated plasma metanephrines and remainder of the biochemical evaluation were unremarkable. Given concern for potential pheochromocytoma, the patient was referred for surgical evaluation and consideration of adrenalectomy. Adrenal artery aneurysm. CT angiogram demonstrated a mass arising from a branch of the right adrenal artery with increased uptake on arterial phase and separate from the adrenal gland, consistent with a right adrenal artery aneurysm (Figure 2). On MRI, the lesion was low intensity on T1 and moderately hyperintense on T2 without evidence of intralesional flow. Given the increased arterial uptake and concern for aneurysm rather than pheochromocytoma, multidisciplinary discussion ensued, and the patient ultimately was planned for angiography and coil embolization with a two-week course of pre-procedural alpha blockade. Angiography demonstrated a 3.1 cm aneurysm arising from the inferior right adrenal artery (Figure 3a) and was subsequently successfully coil embolized resulting in thrombosis of the aneurysm (Figure 3b). After aneurysm embolization, repeat urine normetanephrines were not repeated.Figure 3(a) Right renal artery aneurysm embolization. (b) Right adrenal artery aneurysm, post-embolizationView Large Image Figure ViewerDownload Hi-res image Download (PPT) Visceral arterial aneurysms are rare, with an incidence of 0.1 to 0.2 percent, and affect primarily the hepatic and splenic arteries (60-70 percent), and less commonly celiac and superior mesenteric arteries1Chaer R.A. Abularrage C.J. Coleman D.M. et al.The Society for Vascular Surgery clinical practice guidelines on the management of visceral aneurysms.J Vasc Surg. 2020; 72: 3S-39SAbstract Full Text Full Text PDF PubMed Scopus (219) Google Scholar. Adrenal artery aneurysms are uncommon, with eleven previously reported cases and are often discovered, and subsequently treated, after rupture2Sleightholm R. Wahlmeier S. Carson J.S. Drincic A. Lazenby A. Foster J.M. Massive adrenal vein aneurysm mimicking an adrenal tumor in a patient with hemophilia A: a case report and review of the literature.J Med Case Rep. 2016; 10: 343Crossref PubMed Scopus (3) Google Scholar. In other cases, they may be identified incidentally, as in this case. Spontaneous rupture has been described in cases of uncontrolled hypertension, presumed aortic aneurysm rupture, and in third trimester pregnancy due to high blood flow states. Additionally, adrenal artery pseudoaneurysms may occur secondary to trauma, iatrogenic causes including biopsy or surgery, or oncologic etiologies such as tumor vascular invasion3Fowler A.M. Burda J.F. Kim S.K. Adrenal artery embolization: anatomy, indications, and technical considerations.AJR Am J Roentgenol. 2013; 201: 190-201Crossref PubMed Scopus (38) Google Scholar. While there are not currently standardized guidelines, definitive management of adrenal artery aneurysm is typically pursued upon discovery regardless of size or symptoms due to risk of rupture. Treatment options include angioembolization and surgical exploration and ligation. In some reports, angiography has been used for stable aneurysms or retroperitoneal bleeding and surgical exploration pursued for hemodynamic instability and significant bleeding or for incidental aneurysms discovered intraoperatively3Fowler A.M. Burda J.F. Kim S.K. Adrenal artery embolization: anatomy, indications, and technical considerations.AJR Am J Roentgenol. 2013; 201: 190-201Crossref PubMed Scopus (38) Google Scholar. The case presented demonstrates the importance of consideration of adrenal artery aneurysms in the differential diagnosis of adrenal masses and reviews management considerations once diagnosed.