Endocrine Abstracts

Introduction: Adrenocortical tumors (ACTs) are usually divided in adenoma (ACA) or carcinoma (ACC) according to histopathologic methods. Some lesions are occasionally difficult to classify according to these criteria. We studied the use of some immunohistochemical markers to recognise the difference between malignant and benign tumors.

Materials and methods: We studied 12 patients affected by ACC and 10 by ACA. Clinical evaluation and hormone analysis were performed in all patients who underwent to adrenalectomy. Immunohistochemisty was performed on adrenal tumours tissue except for a singular case in which materials come from lymph node metastasis. We analysed Ki-67, IGF2, Ghrelin, PPARγ, and ACTH expression.

Results: All ten ACAs showed a low Ki-67 <5%, while 4 out of 12 (33%) ACCs showed a high proliferative index (Ki-67>5%). The Wilcoxon–Mann-Whitney U test demonstrated difference between ACAs and ACCs for Ki-67 (P>0.025). We didn’t find statistically significant differences between IGF2 (P<0.0462), Ghrelin (P<0.738), PPARγ (P<0.403), and ACTH (P<0.369). Although there were not differences for IGF2 between the two groups, we observed an overexpression of this marker in 50% of ACC (IGF2>60%). Analysis based on Spearman correlation didn’t find correlation between stage disease, tumor dimension and immunohistochemical markers in ACCs.

Conclusion: According to the literature, we found Ki-67 could be able to distinguish between ACAs and ACCs. Although many studies considered IGF2 as a malignant parameter, our results didn’t confirm its use alone could be helpful to identify malignant lesions. Besides we showed the other different immunohistochemical markers, less commonly investigated in these tumors, should not be useful to discriminate adenoma from carcinoma. None immunohistochemical marker considered in our study showed a correlation with the characteristics of size or local extension of lesions. Therefore, we need more studies about a higher number of patients to obtain much more significant data about IHC utility.