Autopsy report and review of the 2016 WHO classification of congenital supratentorial embryonal tumors, not otherwise specified

Abstract

Purpose: Central nervous system embryonal tumors, not otherwise specified (ETNOS), comprise a group of rare, poorly differentiated embryonal neoplasms of neuroectodermal origin (WHO grade IV) that lack the specific histopathological features and molecular alterations that define other embryonal tumors, such as medulloblas toma and embryonal tumors with multilayered rosettes, C19MC altered. ETNOS accounts for less than 0.5% of all brain tumors and predominantly affects children aged 0–14 years. Case report: The authors report an autopsy case of ETNOS in a female newborn of 22 weeks of gestational age. The brain weighed 68.0 g and measured 61.0 mm in occipitofrontal diameter. A white-gray, soft, infiltrative tumor measuring 0.9 cm in the largest dimension was found in the right lateral ventricle. Microscopic exami nation revealed a high-grade malignant neoplasm composed of small round blue cells, with marked atypia, solid pattern, and high mitotic index. Neoplastic cells showed positive immunostaining for synaptophysin, GFAP, NFP, CD99, INI1, vimentin, and EMA. The diagnosis of ETNOS was thus established. Differential diagnosis includes other embryonal tumors, such as medulloepithelioma, neuroblastoma, ganglioneuroblastoma, and atypical rhabdoid/teratoid tumor. Treatment is usually surgical resection combined with craniospinal irradiation and/or multimodality chemotherapy. Conclusions: Congenital ETNOS are rare high-grade pediatric tumors, probably originated from primitive neu roepithelial cells. Overall, neoplastic cells are positive for synaptophysin, GFAP, INI1, and CD99. Immunohis tochemistry panels are fundamental to establish the diagnosis.