Rosette-forming glioneuronal tumor: report of a chiasmal-optic nerve example in neurofibromatosis type 1: special pathology report.
OBJECTIVE
Rosette-forming glioneuronal tumor is a rare, rather recently described tumor featuring a highly distinctive, biphasic histological pattern, including a cytologically uniform neuronal component of Homer-Wright type pseudorosettes and an accompanying astrocytic element resembling pilocytic astrocytoma. Its occurrence in the posterior fossa and association with the fourth ventricle is stereotypical and a feature of all reported cases.


METHODS
In this article, we describe the first rosette-forming glioneuronal tumor arising outside this site, a histologically classic example involving the anterior visual pathway and associated with neurofibromatosis type 1.


METHODS
Genetic (fluorescent in situ hybridization) studies demonstrated no large deletion in either normal or neoplastic tissue, indicating that the genetic abnormality underlying neurofibromatosis type 1 in this patient is likely a very small deletion or point mutation.


CONCLUSIONS
The relation of the tumor to the underlying neurofibromatosis type 1 cannot be assessed.
Department of Pathology and Laboratory Medicine, Mayo Clinic, Rochester, Minnesota, USA. scheithauer.bernd@mayo.edu
Bernd W
BW
Scheithauer
Ana I
AI
Silva
Rhett P
RP
Ketterling
J H
JH
Pula
James F
JF
Lininger
Mark J
MJ
Krinock
D001254:Astrocytoma / Q000473:pathology; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D009456:Neurofibromatosis 1 / Q000473:pathology*; D009897:Optic Chiasm / Q000473:pathology*; D019574:Optic Nerve Neoplasms / Q000473:pathology*; D055815:Young Adult