Uterine teratomas: a report of clinicopathological features of five tumours

INTRODUCTION: Teratomas are the most common germ cell tumours in the gynaecological tract, the vast majority arising in the ovary. Limited information is available on uterine teratomas. METHODS: We evaluated clinicopathological features of five uterine teratomas, fluorescence in situ hybridization for isochromosome 12p [i(12p)], short tandem repeat (STR) analysis, and targeted DNA sequencing in a subset. RESULTS: Patients' age ranged from 29 to 60 (median: 40) years. Three underwent hysterectomy and two conservative cervical excisions. All tumours were uterine confined with four centred in the cervix and one in the corpus, ranging from 2.4 to 6.5 (median: 3.75) cm. Three tumours only had mature elements with one associated with mature glial tissue in the peritoneum and endometrium. The other two tumours also showed immature neural tissue, warranting a diagnosis of Grade 2 immature teratoma based on ovarian criteria. Four patients were alive with no evidence of disease with median follow-up of 13 (range 2-42) years. i(12p) was not detected in two tumours with available material (one mature and one immature). STR analysis showed heterozygosity in one mature and complete homozygosity in one immature teratoma. Targeted DNA sequencing revealed no pathogenic or likely pathogenic alterations in one immature teratoma and a pattern consistent with genome-wide loss of heterozygosity. CONCLUSIONS: Uterine teratomas display either mature or an admixture of mature and immature elements and can rarely be associated with gliomatosis. Limited data show no association with i(12p). The malignant potential of immature uterine teratomas is not well established and they appear to be more akin to sacrococcygeal than ovarian teratomas based on limited STR results from this cohort and the literature.