Comparison of Ki-67 index values between patients with operated giant prolactinomas and macroprolactinomas

Abstract

Objective: Data on whether there is a histopathological difference in cellular features as determined with Ki-67 between giant prolactinomas and smaller macroprolactinomas are not fully clear. In this study, we aimed to compare Ki-67 value between patients followed-up with diagnosis of macroprolactinoma and giant prolactinoma and operated for different reasons. Methods: Files of 15 patients with giant prolactinomas and 16 patients with macroprolactinomas who had been operated with various indications were retrospectively evaluated. Similar number of patients were included to carry out a reasonable analysis. Patients’ demographics (age and gender), age at the time of diagnosis, tumor diameter during the diagnosis and at the last follow-up visit, initial and last PRL and Ki-67 values were compared between the groups. Ki-67 value was studied with MIB-1 monoclonal antibody method. Results: The mean age and gender were similar between the patients with macroprolactinomas and giant prolactinomas. The mean longest tumor diameter at diagnosis was measured as 18.13±9.42 mm in the macroprolactinoma and 47.07±9.70 mm in the giant prolactinoma group (p<0.001). The mean PRL level at diagnosis was found as 4534.93±12923.56 in the macroprolactinoma and 5513.08±7077.87 in the giant prolactinoma group (p=0.008). The mean Ki-67 value was found as 31.06±28.82 in the macroprolactinoma and 31.60±30.78 in the giant prolactinoma group. There was no significant difference between the groups in the Ki-67 values (p=0.922). Conclusion: Ki-67 value was similar between macroprolactinomas and giant prolactinomas, suggesting that mitotic activity as determined by Ki-67 value is not practical in indicating growth and proliferation characteristics of prolactinomas.

Keywords

• Macroprolactinoma
• giant prolactinoma
• pituitary adenoma
• Ki-67
• proliferation
• biological behavior

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