Inflammation in the neoplasms of the adrenal gland: Is there a prognostic role? An immunohistochemical study

Introduction: Adrenal gland neoplasms are mostly benign. The differential diagnosis between adrenocortical adenoma and carcinoma relies on nine morphologic parameters (Weiss criteria) that are mostly subjective. Although rare, carcinomas represent an aggressive disease that require short time follow-up. For this reason, the diagnosis should be accurate. Neoplasms of the medulla are mostly represented by phaeochromocytomas, all potentially metastatic. Prognostic score systems (GAPP and PASS) have been implemented but not enough objective and useful in borderline cases. More objective parameters should be introduced. Little is known in literature on the inflammatory response in these tumors. Aim of our study was the definition (type, density and distribution) of inflammation in the adrenal neoplasms. Material and methods: Immunohistochemistry for CD45 (inflammatory cells), CD20 (B cells) and CD3 (T cells) antibodies was performed in 15 adrenocortical neoplasms and 17 phaeochromocytomas. A manual count of the signal was set for each marker, to establish the cellular type, their density (cells/mm2) and location within the tumor. Fisher's exact test was applied to assess the correlation between the immunoscore and clinico-pathologic parameters. Results: The difference of cellular density between the three markers was statistically significant (p value = 0.0028), with highest values for CD45 and CD3. No differences were detected between the periphery and the center of the lesions. The most relevant finding was the detection of a higher immunoscore in adrenocortical adenomas, compared to carcinomas. Moreover, most of phaeochromocytomas showed high expression of inflammation, except the only metastatic case. Conclusions: The present study showed that inflammation could represent a valuable diagnostic and potential prognostic parameter, useful for the correct management of these lesions.