Embryonal tumor with abundant neuropil and true rosettes: morphological, immunohistochemical, ultrastructural and molecular study of a case showing features of medulloepithelioma and areas of mesenchymal and epithelial differentiation

Neuropathology. 2010 Feb 1;30(1):84-91. doi: 10.1111/j.1440-1789.2009.01040.x. Epub 2009 Jun 25.

Abstract

Embryonal tumors are a group of malignant neoplasms that most commonly affect the pediatric population. Embryonal tumor with abundant neuropil and true rosettes is a recently recognized rare tumor. It is composed of neurocytes and undifferentiated neuroepithelial cells arranged in clusters, cords and several types of rosettes in a prominent neuropil-rich background. We describe a new case of this tumor. The patient, a 24-month-old female infant, was referred to the Meyer Children's Hospital with a history of right brachio-crural deficit associated with occasional episodes of headache and vomiting. Computed tomography scan and MRI revealed a large bihemispheric mass. The patient underwent two consecutive surgeries. The resultant surgical resection of the tumor was macroscopically complete. The postoperative period was uneventful. On light microscopy the tumor showed a composite morphology: embryonal tumor with abundant neuropil and true rosettes (specimen from the first surgery); medulloepithelioma with mesenchymal and epithelial areas (specimen from the second surgery). The immunohistochemistry evidenced the heterogeneous (neuronal, mesenchymal and epithelial) immunoprofile of tumoral cells. By real-time polymerase chain reaction (RT-PCR), the PTEN gene expression in the tumor was lower than in the five non-neoplastic brain tissues used as control. Mutation analysis did not show any variation in INI-1 and PTEN sequence while P53 analysis showed the presence of homozygote P72R variation. Fluorescent in situ hybridization analysis showed polysomy of chromosome 2 while amplification of N-MYC was not detected. Owing to the rarity of embryonal tumor with abundant neuropil and true rosettes, each new case should be recorded to produce a better clinical, pathological and molecular characterization of this lesion.

Publication types

  • Case Reports

MeSH terms

  • Aneuploidy
  • Brain / metabolism
  • Brain / pathology
  • Brain / ultrastructure
  • Brain Neoplasms / metabolism
  • Brain Neoplasms / pathology*
  • Brain Neoplasms / surgery
  • Cell Differentiation
  • Child, Preschool
  • Chromosomal Proteins, Non-Histone / genetics
  • Chromosomes, Human, Pair 2
  • DNA-Binding Proteins / genetics
  • Epithelium / metabolism
  • Epithelium / pathology
  • Epithelium / ultrastructure
  • Female
  • Genes, myc
  • Humans
  • Immunohistochemistry
  • Mesoderm / metabolism
  • Mesoderm / pathology
  • Mesoderm / ultrastructure
  • Mutation
  • Neoplasms, Germ Cell and Embryonal / metabolism
  • Neoplasms, Germ Cell and Embryonal / pathology*
  • Neoplasms, Germ Cell and Embryonal / surgery
  • Neuroectodermal Tumors, Primitive / metabolism
  • Neuroectodermal Tumors, Primitive / pathology*
  • Neuroectodermal Tumors, Primitive / surgery
  • Neuropil / metabolism
  • Neuropil / pathology*
  • Neuropil / ultrastructure
  • PTEN Phosphohydrolase / genetics
  • PTEN Phosphohydrolase / metabolism
  • SMARCB1 Protein
  • Transcription Factors / genetics
  • Tumor Suppressor Protein p53 / genetics

Substances

  • Chromosomal Proteins, Non-Histone
  • DNA-Binding Proteins
  • SMARCB1 Protein
  • SMARCB1 protein, human
  • Transcription Factors
  • Tumor Suppressor Protein p53
  • PTEN Phosphohydrolase
  • PTEN protein, human