Imaging phenotype is useful in characterisation of adrenal lesions, as suggested by Miller and colleagues1; however, some important points have not been addressed in their review. First, size of adrenal mass is a major predictor of malignant disease, independent of imaging characteristics. A cut-off of 4.0cm has been proposed as having the highest sensitivity (93%) in differentiating between benign and malignant tumours2. Risk of cancer is 2 % for tumours less than 4 cm and 6% for the tumours 4-6 cm in diameter. As this risk increases to 25% for tumours larger than 6 cm in diameter, most experts recommend consideration for surgery in such patients.

Second, Pheochromocytomas commonly exhibit certain imaging characteristics otherwise associated with primary adrenal carcinoma and metastasis, namely; large size, prominent vascularity, increased density (>10 Hounsfield units), cystic and haemorrhagic areas on unenhanced CT, slow delayed contrast washout (<_50 _="_" at="at" _10="_10" minutes="minutes" and="and" high="high" signal="signal" intensity="intensity" on="on" t2-weighted="t2-weighted" mri34.="mri34." biochemical="biochemical" testing="testing" should="should" therefore="therefore" be="be" routinely="routinely" done="done" in="in" all="all" patients="patients" with="with" adrenal="adrenal" mass.="mass." p="p"/> Third, adrenal insufficiency as well as adrenocortical hyperfunction should be considered in patients with bilateral adrenal masses4.

May I also add that the title “definitive characterisation of adrenal lesions” is possibly an overstatement as that can only truly be expected from a histological investigation.

References

1. Miller JC, Blake MA, Boland GWL. Definitive characterisation of adrenal lesions. BMJ 2009; 338:a3092. (24 January )

2. Mantero F, Terzolo M, Arnaldi G, et al. A survey on adrenal incidentaloma in Italy. J Clin Endocrinol Metab 2000; 85:637-644.

3. Motta-Ramirez GA, Remer EM, Herts BR, Gill IS, Hamrahian AH. Comparison of CT findings in symptomatic and incidentally discovered pheochromocytomas. AM J Roentgenol 2005;185:684-8

4. Young WF Jr. Clinical Practice. The Incidentally discovered adrenal mass. N Engl J Med 2007; 356:6

Competing interests: None declared