Fetal presentation of congenital fibrosarcoma of the meninges: case report and literature review

Aim: Congenital infantile fibrosarcoma (CIFS) exceptionally occurs in the meninges, with no cases reported before or at birth. We report herein a meningeal CIFS diagnosed in a fetus at 40 weeks of gestation (WG). Case report: A 24-year-old pregnant woman was referred to the obstetrics department for vaginal bleeding. A severe right hydrocephalus due to a large tumor invading the left hemisphere and ventricles was discovered in the fetus, and medical termination of the pregnancy was achieved. Results: Histological examination revealed a highly cellular spindle or ovoid shaped cell proliferation organized in interlacing bundles; it was diffusely positive for vimentin, and scarcely for SMA (smooth muscle actin). NFs (neurofilaments), NeuN, S100 protein, desmin, GFAP (glial fibrillary acidic protein), Olig2, chromogranin, synaptophysin, CD31, CD34, BCL2, and EMA (epithelial membrane antigen) antibodies were negative. Ki67 antibody labeled 20% of the nuclei. A reverse transcription polymerase chain reaction assay was performed to detect the gene fusion ETV6-NTRK3 transcript. Despite negative results, it was concluded to be a CIFS of the meninges. Discussion: CIFS of the meninges during the fetal period has never been reported. Its diagnosis is based on immunohistochemistry, and, whenever possible, on the detection of the reciprocal translocation t (12;15) resulting in the gene fusion ETV6-NTRK3. Its prognosis depends on rapid growth and local invasiveness leading to cerebral structure damage.