Gliomatosis peritonei is associated with frequent recurrence, but does not affect overall survival in patients with ovarian immature teratoma.

Gliomatosis peritonei (GP) is commonly associated with ovarian teratoma and is not thought to have an adverse prognostic effect. However, the prognostic impact and characteristics of GP remain to be clarified. In this study, we investigated the clinicopathologic features of ovarian teratoma associated with GP, and we further compared ovarian immature teratoma (IT) with GP to ovarian IT without GP. During the study period, there were a total of 16 ovarian teratomas associated with GP. Among them, 15 cases were ovarian ITs of various grades. When ovarian IT with GP (n = 15) was compared to ovarian IT without GP (n = 27), it was found that ovarian IT patients with GP had larger tumor size (median, 19 vs. 13 cm; P < 0.001), more frequent recurrence (40 %, 6/15 vs. 3.7 %, 1/27; P = 0.005), and frequently elevated preoperative CA-125 level (100 %, 12/12 vs. 50 %, 10/20; P = 0.004). All recurrences occurred within 2 years of the initial surgery. Survival curves indicated that ovarian IT patients with GP had significantly shorter recurrence-free survival compared to those without GP (P = 0.002). The 2-year recurrence-free survival rates were 59.3 and 96.3 % in IT with GP and IT without GP, respectively. However, all but one case of IT with GP are currently alive. In conclusion, GP is an adverse prognostic factor characterized by frequent recurrence in patients with ovarian IT.