Histopathological differentiation between adrenocortical adenoma and carcinoma is prognostically important. The Weiss scoring system is considered the most popular multiparametric scoring system. The potential role of immunohistochemical expression of proliferation markers as an ancillary technique for the assessment of malignancy in adrenocortical neoplasms was evaluated.
The aim of the present study was to evaluate the role of immunohistochemical expression of metallothionein and Ki-67 antigen in comparison to histopathology in differentiation between benign and malignant adrenocortical tumors.
In all, 35 cases were studied: 14 adrenocortical carcinomas, 13 adrenocortical adenomas, and eight cases of normal adrenal cortex to serve as control. All hemotoxylin and eosin sections were carefully reviewed for Weiss criteria. Three nuclear features were included in the Weiss system: high nuclear grade, mitosis greater than 5/50 high power field, and atypical mitoses, creating a new score called the nuclear score was evaluated. Immunohistochemical detection of metallothionein and Ki-67 antigen expression for each tumor was done.
The expression of metallothioneins (MT) and Ki 67 in all cases of adenoma showed very weak faint cytoplasmic and nuclear staining, respectively. The expression of MT in all carcinoma cases showed diffuse strong to moderate cytoplasmic staining, while Ki-67 expression showed diffuse strong to moderate nuclear staining. Tumor size, total Weiss score, nuclear score, and each of the Weiss criteria except for diffuse pattern and MT expression level showed a statistically significant difference between adenomas and carcinomas.
The expression of both MT and Ki-67 antigen is significantly higher in adrenocortical carcinomas than in adrenocortical adenomas, so these markers can be considered as reliable indicators of malignancy in a suspicious adrenocortical tumor. A new nuclear score was created by the present study to show the importance of the nuclear features as a differentiating point between adenoma and carcinoma as well as the prognostic significance of that score in patient survival and clinical outcome.
Department of Pathology, Faculty of Medicine, Alexandria, Egypt
Correspondence to Dina Abdallah, PhD, Department of Pathology, Alexandria Faculty of Medicine, 20, Yehye Elmashat Street, Smouha, Alexandria 21431, Egypt Tel: +20 100 567 6635; e-mail: firstname.lastname@example.org
Received February 13, 2018
Accepted March 8, 2018