Discerning malignancy in resected adrenocortical neoplasms

Differential diagnosis between adenoma and carcinoma in resected human adrenocortical neoplasms may be one of the most problematic and difficult areas of surgical pathology practice. This is especially true in cases of relatively small adrenocortical tumors not associated with obvious signs of malignancy such as necrosis and/or hemorrhage. In addition, the numbers of these small adrenocortical neoplasms are increasing owing to the widespread application of sophisticated computed tomography and/or magnetic resonance imaging scans. No single parameter can be effective in this differential diagnosis of resected adrenocortical tumor. Histopathologic evaluation using a multivariate scoring system is considered most effective in discerning malignancy and biologic behavior of resected adrenocortical neoplasms. Molecular and cellular findings of adrenocortical carcinoma have been inconsistent except for the increased cell proliferation associated with adrenocortical malignancy. Therefore, an assessment of neoplastic cell proliferation using immunostains of cell cycle-associated nuclear antigen such as Ki-67 is the only useful auxiliary method of evaluating malignancy in resected adrenocortical neoplasms at present.