СONGENITAL MEDULLOBLASTOMA: PRENATAL AND POSTNATAL MRI FINDINGS

Abstract

Background. Medulloblastoma represents the most common malignant pediatric brain neoplasm accounting for 15–20 % of brain tumors in childhood. However, congenital medulloblastomas are extremely rare and mostly diagnosed postnatally. to the best of our knowledge, only one case was reported where this tumor was detected antenatally by ultrasound. MRI features of fetal medulloblastoma have not been described to date. Material and methods. We present MRI findings of fetal medulloblastoma progression from the 31st week of gestation until 5.5 months of postnatal life. Histopathological, genetic and molecular parameters were studied. after partial tumor removal and chemotherapy, MRI images demonstrated complete tumor response to therapy. the follow-up period was 1.5 years. Results. Fetal MRI performed on the 31st gestational week revealed a midline cerebellar lesion of ≤2 cm in size with minor t2 hypointensity and t1 hyperintensity. additionally, a restricted diffusion on aDc-maps depicted the lesion most conspicuously. the advantage of DWI over traditional t1- and t2-VI was associated with a relatively lower diffusion coefficient in the tumor (0.63×10–3 mm2/s) compared with the surrounding medulla (0.98×10-3 mm2/s). Histopathological, genetic and molecular studies revealed desmoplastic medulloblastoma with high nodularity, cMYc/NMYc-negative, МхR+. combined treatment using 5 cycles of HIt-sKK chemotherapy by HIt MED 2014 protocol (version 2017) in a highly specialized pediatric oncology center resulted in a stable tumor remission. Conclusion. Fetal MRI with DWI is the most effective approach for early detection of congenital medullobastoma. Early prenatal diagnosis, as well as postnatal verification and classification of congenital medulloblastomas is critical for timely treatment planning and good outcome.

Keywords

• врожденная медуллобластома
• опухоли мозга плода
• магнитно-резонансная томография
• мрт
• диффузионно-взвешенные изображения