Background: Adrenal tumors affect 3–10% of world population.
Aquaporin2 is water channel protein that is widely distributed
among mammalian tissues and plays a major role in water
homeostasis. However, little is known about the expression and
significance of AQP2 in human adrenal tumors. Aim: To
evaluate the diagnostic significance of expression of AQP2 in
primary adrenal gland tumors and correlate the results with
different clinico-pathological variables. Material and Methods:
This is a retrospective, selected, controlled study carried on 44
adrenal gland lesions included (14) adrenocortical adenoma, (10)
adrenocortical carcinoma and (20) pheochromocytoma.
Clinicopathological characteristics of examined cases were
correlated with the IHC expression of Aquaporin2. Results:
Positive IHC expression of AQP2 was detected in 100%, 40%
and 35.7% of studied cases of pheochromocytoma, ACA and
ACC cases respectively. Among pheochromocytoma, 15% the
cases show focal expression (+1), 40% of cases show
intermediate expression (+2) and 45% of cases show diffuse
expression (+3). Sensitivity and specificity of AQP2 in diagnosis
of pheochromocytoma were 100% and 87.5% respectively.
Conclusion: The results suggested that AQP2 is a diagnostic
marker of pheochromocytoma and can differentiate it from
adrenocortical adenoma and adrenocortical carcinoma but cannot
differentiate between both adrenocortical adenoma and
adrenocortical carcinoma