title: 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.
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.
authors: Department of Biomedicine, Careggi Hospital, 50134 Florence, Italy. ambuccoliero@unifi.it
authors: Anna Maria
authors: AM
authors: Buccoliero
authors: Francesca
authors: F
authors: Castiglione
authors: Duccio
authors: D
authors: Rossi Degl'Innocenti
authors: Alessandro
authors: A
authors: Franchi
authors: Milena
authors: M
authors: Paglierani
authors: Massimiliano
authors: M
authors: Sanzo
authors: Valentina
authors: V
authors: Cetica
authors: Laura
authors: L
authors: Giunti
authors: Iacopo
authors: I
authors: Sardi
authors: Lorenzo
authors: L
authors: Genitori
authors: Gian Luigi
authors: GL
authors: Taddei
mesh_terms: D000782:Aneuploidy; D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D001932:Brain Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D002454:Cell Differentiation; D002675:Child, Preschool; D002868:Chromosomal Proteins, Non-Histone / Q000235:genetics; D002889:Chromosomes, Human, Pair 2; D004268:DNA-Binding Proteins / Q000235:genetics; D004848:Epithelium / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D005260:Female; D016259:Genes, myc; D006801:Humans; D007150:Immunohistochemistry; D008648:Mesoderm / Q000378:metabolism / Q000473:pathology / Q000648:ultrastructure; D009154:Mutation; D009373:Neoplasms, Germ Cell and Embryonal / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D018242:Neuroectodermal Tumors, Primitive / Q000378:metabolism / Q000473:pathology* / Q000601:surgery; D019581:Neuropil / Q000378:metabolism / Q000473:pathology* / Q000648:ultrastructure; D051059:PTEN Phosphohydrolase / Q000235:genetics / Q000378:metabolism; D000071796:SMARCB1 Protein; D014157:Transcription Factors / Q000235:genetics; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
chemical_list: D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D000071796:SMARCB1 Protein; C513266:SMARCB1 protein, human; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human