Large Adrenal Tumors: Does Size Really Matter?

Presentation Number: SUN 381
Date of Presentation: April 2nd, 2017

Nicole M Iniguez Ariza*1, Jacob D Kohlenberg2, Danae Anastasia Delivanis3, Melinda Thomas3, Robert P Hartmann4, Muhammad Z Shah5, Diana S. Dean3, Justine Herndon3, Travis J. McKenzie3, William F Young Jr.3 and Irina Bancos3
1Mayo Clnic, Rochester, MN, 2Mayo Clinic Rochester, Rochester, 3Mayo Clinic, Rochester, MN, 4Mayo Clinic, MN, 5University of Minnesota, Minneapolis, MN



Adrenal tumors occur in 5% of adults but only a minority are >4 cm in diameter. Size is associated with malignancy and surgery is frequently recommended for tumors >4 cm, but the specificity of tumor size is poor. Evidence on clinical presentation and natural history of patients with large adrenal tumors is lacking.


Our aim was to delineate the clinical, biochemical, and imaging characteristics of adrenal tumors ≥4 cm and to identify features associated with malignancy.


We retrospectively reviewed adult patients diagnosed with an adrenal tumor ≥ 4 cm in diameter between 2000 and 2014 at Mayo Clinic, Rochester.


Of 4085 patients with adrenal masses, 699 (17%) were ≥4 cm in diameter (53% women, median age = 59 yrs [range, 18-91]). Adrenal tumors included: 215 (31%) cortical adenomas; 110 (16%) non-cortical benign adrenal tumors (myelolipoma, cyst, ganglioneuroma, etc.); 157 (22%) pheochromocytomas (PHEO); 87 (12%) adrenal cortical carcinoma (ACC); and, 130 (19%) malignant non-cortical adrenal tumors (metastasis, lymphoma, etc). Modes of tumor discovery included: incidental on imaging in 465 (67%); due to symptoms of adrenal hormonal excess in 107 (15%); cancer staging imaging in 62 (9%); symptoms of mass effect in 51 (7%); and, B symptoms in 14 (2%) patients. Median tumor size was 5.2 cm (range, 4-24.4). The 455 (65%) patients treated with adrenalectomy: were younger (54 ± 16 vs 63 ± 14 yrs, P<.0001); were more likely to have hormonal excess; had larger tumor size (7.1 ± 2.4 vs 5.9 ± 3.9 cm, P<.001); more frequently had unilateral mass (91% vs 76%, P<.0001); and, had higher unenhanced radiodensity (24 ± 33 vs 8 ± 30, P=.001).

Malignant adrenal tumors were less frequently diagnosed incidentally (45% vs 86%, P<.001), had larger size (7 cm; range, 4-24 vs 5 cm; range, 4-20) (P<0.001) and higher radiodensity (34 ± 11 HU vs 8 ± 34 HU, P<.001) than benign tumors. In comparison to women, men had lower prevalence of ACC (36% vs 63%) but higher prevalence of other malignancy (65% vs 35%) and overall malignancy (53% vs 47%, P=.03). Patients with ACC were diagnosed at a younger age (50 yrs; range, 19-85) when compared to patients with other malignant adrenal tumors (65 yrs; range 18-87) and benign adrenal tumors (59 yrs; range, 20-91), P<.001.


Patients with large adrenal tumors are most frequently diagnosed incidentally and encompass a heterogeneous group. Tumor diameter by itself is not a reliable determinant of malignancy. Overall prevalence of malignancy in patients with adrenal tumors ≥ 4cm was 31%. Risk of malignancy was associated with age of diagnosis and gender, non-incidental mode of discovery, larger tumor size and indeterminate imaging characteristics. We suggest that patient context, hormonal assessment and computed image phenotype can better guide the need for adrenalectomy in patients with tumors ≥4 cm in diameter.


Nothing to Disclose: NMI, JDK, DAD, MT, RPH, MZS, DSD, JH, TJM, WFY Jr., IB