Gliomatosis peritonei in childhood and adolescence. Clinicopathological study of 13 cases including immunohistochemical findings.

Gliomatosis peritonei (GP) can be defined as the metastatic implantation of neural tumor tissue on surfaces of the peritoneum in patients with immature ovarian teratomas. Data from 13 patients with GP were evaluated. The average age at time of biopsy was 11 years (median: 11.5 years; range: 2.9 to 18.6 years); average time of follow-up was 26.6 months (median: 22 months; range: 4 to 77 months). In 11/13 patients the GP was discovered at the same time as the primary tumor, in two patients it was detected at second-look surgery. Degree of maturity according to scheme of Robboy and Scully was 8 x G 1, 4 x G 2, and 1 x G 3 for the ovarian teratomas (x = 1.46), and 11 x G 0 and 2 x G 3 for the GP implants (x = 0.46). Light microscopically, the mature glial nodules consisted almost exclusively of GFAP and S-100 protein positive astroglia. Twelve of the 13 patients are alive and clinically healthy. One patient with metachronic immature GP is receiving chemotherapy. In general, the prognosis for GP is good: it depends chiefly on the degree of maturity of the implants. In mature GP, usually no additional chemotherapy is necessary; in immature GP, chemotherapy can induce maturation of the implants.