This was later modified by Norris et al. (1976), who added a quantitative aspect to the degree of immaturity. Karyotype
An ovarian immature teratoma is karyotypically normal 46,XX or near-normal. Grade 1 or 2 tumors exhibit 46,XX normal karyotype, whereas grade 3 tumors show a variety of abnormal karyotypes. Though immature teratoma cells show a normal karyotype, there may still be detectable alterations in the gene level and that these aberrations may influence the stability of chromosome status. Genetics
Ovarian immature teratomas have been classified as among the least mutated of all solid cancers. Immature teratomas originate from germ cells that undergo one of several meiotic failures, leading to a tumor genome with high levels of copy neutral loss of heterozygosity. Prognosis
Though several studies have shown that size and stage of the primary tumor are related to survival, the grade of the tumor is the best determinant of prognosis prior to peritoneal spread. Once peritoneal spread has occurred, the grade of metastatic lesions or implants is the best determinant of prognosis. Multiple sections of the primary tumor and wide sampling of the implants are necessary to properly grade the tumor. In most cases, the implants are better differentiated than the primary tumors. Gliomatosis peritonei, a rare condition often associated with immature ovarian teratoma, is characterized by the presence of mature glial implants in the peritoneum. Yoon et al.
(2012), reported that immature ovarian teratoma patients with Gliomatosis peritonei have larger tumors, more frequent recurrence and higher CA-125 levels than immature ovarian teratoma patients without gliomatosis peritonei.A high degree of immaturity in the primary tumor, one that corresponds with a grade 3 diagnosis is a sign of poor prognosis. Grade 3 tumors often display chromosomal abnormalities, also an indication of poor prognosis. Tumor grade is the most important factor for relapse in immature teratomas. Vicus et al. (2011), reported that grade 2 or 3 tumors are associated with a greater chance of relapse that can be fatal, predominantly within 2 years of diagnosis. Among grade 3 patients, the stage was significantly associated with relapse.In the past, survival rates were low for high-grade immature teratomas. Norris et al. (1976), reported a survival rate of 82% for patients with grade 1 tumors, 62% for grade 2 and 30% for grade 3 tumors. However, these results antedate the use of multi-agent chemotherapy. With the advent of multiagent chemotherapy after surgical resection, long-term remission and increased survival rates have been achieved. Pashankar et al. (2016), reported that the estimated 5-year overall survival rate for grade 3 Stage I and II disease was 91%  compared with 88% for grade 3, Stage III and IV disease. Treatment
Histologic grade and fertility desires of the patient are key considerations in determining treatment options. In adult women postoperative adjuvant chemotherapy is standard except for stage I /grade 1 disease. In pediatric patients, surgery alone is standard.