In recent years, few studies have specifically focused on only histological features in choroid plexus tumors. We retrospectively reviewed the clinicopathologic and histological features in 37 patients with choroid plexus tumors and correlated these with glial fibrillary acidic protein (GFAP) expression and proliferation cell nuclear antigen (PCNA), p53, p21, and Rb labeling indexes, with special attention to tumor recurrence/regrowth. The study included 24 choroid plexus papillomas (CPPs), 4 atypical choroid plexus papillomas (ACPPs), and 9 choroid plexus carcinomas (CPCs). Patient age ranged from 15 to 70 years (mean 44 years). Most of the choroid plexus tumors were located in the IV ventricle. Recurrence was observed in 21 (52%) cases, 14 of which were CPP and 7 of which were CPC (P = 0.032). Histologic findings included major necrosis, fibrosis and psammoma bodies, amyloid deposits, inflammation, and thick vessels in recurrent tumors. The PCNA labeling index was 52.04 + or - 13.92 in CPPs, 76.50 + or - 17 in ACPPs, and 95.22 + or - 21.34 in CPCs (P = 0.009), and 67.43 + or - 28 in recurrent tumors. Similar values were found for p53, p21, and Rb. Furthermore, we observed that these presented more histological changes, adding, than nonrecurrent tumors, as well as a higher proliferation index of cell-cycle markers, and these were dependent predictor factors of survival. Recurrent tumors showed a different biological behavior than nonrecurrent tumors, but histological observations showed no mitotic features in order to consider them as grade II.