Published ahead of print on August 13, 2008
doi: 10.3174/ajnr.A1233
Pilomyxoid Astrocytoma: Expanding the Imaging Spectrum
L.L. Linscotta,
A.G. Osborna,
S. Blaserb,
M. Castilloc,
R.H. Hewlettd,
N. Wieselthalerd,
S.S. Chine,
J. Krakenesf,
G.L. Hedlundg and
C.L. Suttonh
a Department of Radiology, University of Utah, Salt Lake City, Utah
b Department of Radiology, The Hospital for Sick Children, Toronto, Ontario, Canada
c Department of Radiology, University of North Carolina, Chapel Hill, NC
d Department of Radiology, Red Cross Children's Hospital, University of Cape Town, Cape Town, South Africa
e Department of Pathology, University of Utah, Salt Lake City, Utah
f Department of Radiology, Haukeland University Hospital, Bergen, Norway
g Department of Pediatric Imaging, Primary Children's Hospital, Salt Lake City, Utah
h Department of Radiology, Tulane University, New Orleans, La
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Fig 1. Case 9. A, Axial FLAIR sequence in a 3-year-old girl with progressive blindness shows a large solid lobulated suprasellar and bitemporal PMA, with uniform hyperintensity. B, Coronal contrast-enhanced T1-weighted image shows a homogeneously enhancing suprasellar and bitemporal PMA. C, Photomicrograph shows classic hairlike ("piloid") astrocytes in a myxoid background (hematoxylin-eosin, original magnification x300). D, Photomicrograph shows that the tumor is strongly positive for glial fibrillary acidic protein, confirming its astrocytic origin.
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Fig 2. Case 6. A, Sagittal contrast-enhanced T1-weighted image in a 2-year-old boy with seizures shows a nonenhancing tumor in the posterior parietal cortex. B, Axial T2WI in the same patient shows homogeneous hyperintensity without surrounding edema. PMA was found at surgery.
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Fig 3. Case 13. A, Axial contrast-enhanced T1-weighted image in a 17-year-old boy with intractable headaches shows a rim-enhancing PMA of the cerebellar vermis. B, FLAIR image shows heterogeneous hypertintensity with extension into adjacent white matter of the cerebellar folia. C and D, DWI (C) and apparent diffusion coefficient map (D) show no restricted diffusion. This case demonstrates atypical age, location, and enhancement pattern.
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Fig 4. Case 11. A, Hemorrhage in PMA. Axial NCCT scan in a 24-year-old man with headache, confusion, and gait instability shows a right temporal lobe PMA with fluid-fluid levels and hyperattenuation consistent with hemorrhage. B, Axial contrast-enhanced T1-weighted image shows anteromedial rim enhancement and fluid-fluid levels.
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Fig 5. Case 20. A, Axial T2WI in a 21-year-old man with headache shows a heterogeneous supra- and juxtasellar mass. The hypointense core suggests hemorrhage, which was confirmed at surgery. B, Axial contrast-enhanced T1-weighted image shows a rim-enhancing tumor surrounding a nonenhancing hemorrhagic core. Hemorrhagic exophytic hypothalamic/chiasmatic tumor was partially resected and originally diagnosed as PA in 1997. Re-examination of the specimen in 2007 showed features consistent with PMA.
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Fig 6. Case 7. MR spectroscopy (TE = 135 ms) in a 9-month-old boy with failure to thrive shows increased Cho and lipids with decreased Cr and NAA within the tumor. Multivoxel MR spectroscopy map showed Cho/Cr = 6.1.
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