Immature teratoma

At CT and MRI, an immature teratoma possesses characteristic appearance. It is typically large (12–25 cm) and has prominent solid components with cystic elements. It is usually filled with lipid constituents and therefore demonstrates fat density at CT and MRI. Stage Traditionally, comprehensive surgical staging is performed via exploratory laparotomy with cytologic washings, peritoneal biopsies, an omental assessment (either biopsy or rarely a full omentectomy), and both pelvic and aortic lymph node dissection. Laproscopy is often suggested as an alternative to surgically stage patients with immature teratoma. Ovarian cancer is staged using the FIGO staging system and uses information obtained after surgery, which can include a total abdominal hysterectomy via midline laparotomy, unilateral (or bilateral) salpingo-oophorectomy, pelvic (peritoneal) washings, assessment of retroperitoneal lymph nodes and/or appendectomy. The AJCC staging system, identical to the FIGO staging system, describes the extent of tumor (T), the presence of absences of metastases to lymph nodes (N), the presence or absence of distant metastases (M). Pathology s by incidence and risk of ovarian cancer, with immature teratoma at right. An immature teratoma contains varying compositions of adult and embryonic tissue. The most common embryonic component identified in immature teratomas is the neuroectoderm. Occasionally, tumors may present neuroepithelium that resemble neuroblasts. While mature neural cells have nuclei with uniformly dense chromatin and neither exhibit apoptotic or mitotic activity, immature neural cells have nuclei with vesicular chromatin and exhibit both apoptotic and mitotic activity. Grade Thurlbeck and Scully devised a grading system for "pure" immature teratomas on the basis of differentiation of the cellular elements of the tumor. The proportion of immature tissue elements defines the grade 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. 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. 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. Some physicians recommend ovarian cystectomy alone, rather than a unilateral salpingo-oophorectomy for patients with an early stage low grade disease. Zhao et al. (2017), reported no significant differences in survival rates or post-operative fertility outcomes between the two treatment options. However, others caution against such an approach. Studies like these resulted in the recommendation to use chemotherapy for grade 2 and 3 tumors. Currently, the use of multi agent chemotherapy for adult patients with ovarian immature teratoma is standard of care except for grade 1, stage I tumors. While a prospective comparison of VAC versus BEP has not been performed, in well-staged patients with completely resected tumors, relapse is essentially unheard of following platinum-based chemotherapy. == See also ==