• cervix uteri;
  • DNA typing;
  • lymphoid hyperplasia;
  • teratoma

A rare case of an extragonadal teratoma, which occurred primarily in the uterus, is described. The tumor developed in the uterine cervix as a conventional cervical polyp, 3 months after an elective abortion in a 27-year-old woman. Microscopically, the solid 2.2 × 1.8 × 1.5 cm mass was a mature teratoma with exuberant lymphoid elements. It consisted of ectodermal, mesodermal and endodermal derivatives. The lymphoid elements may have been a lymphoid hyperplasia, a chronic inflammatory reaction or a component of the teratoma. However, as the lymphoid tissues had no spatial relation to the teratomatous components, the possibility of a teratomatous element was excluded. This could be regarded as a result of an immunological reaction to the tissues composing the tumor, rather than just a chronic inflammatory response because the lymphoid reaction was present in the tumor, the tumor–host interface and the perivascular areas. Because of the patient's history of an abortion and a lymphoid reaction, the possibility of fetal remnants implantation was raised, so DNA typing to compare the teratoma portion with a normal portion of the host was performed. We found the teratoma portions to be in accordance with that of the host, and hence ruled out fetal remnants implantation. This case showed that a mature teratoma of the uterine cervix may manifest as a feature of implanted fetal tissue. In addition, a real teratoma should be included in the differential diagnosis of uterine teratomatous lesion, even when detected in patients with a recent history of pregnancy and lymphoid hyperplasia.