Presentation
Seizure.
Patient Data
A fairly well-circumscribed high T2 signal mass in the right frontal lobe demonstrates substantial FLAIR partial suppression (T2 FLAIR mismatch). Peripherally it has a high FLAIR signal rim. It has low T1 signal without contrast enhancement. The mass generally has very facilitated diffusion on ADC and low rCBV. Spectroscopy demonstrates elevated choline and myoinositol peaks and depression of NAA.
Conclusion
Appearances are those of an adult-type diffuse glioma. In this age group, IDH mutations are very common and the presence of partial FLAIR suppression strongly favors this tumor to be an astrocytoma IDH mutant, most likely WHO grade 2, as there are no higher grade features.
Case Discussion
The patient went on to have a resection.
Histology
Sections of cerebral cortex and white matter show a cellular tumor with a loose fibrillary background with occasional microcyst. Tumor cells have angulated to ovoid hyperchromatic nuclei. Occasional gemistocytic forms are present. Mitoses are rare. Necrosis and microvascular proliferation are not present.
Immunohistochemistry
GFAP: Positive
OLIG2: Positive
IDH-1 R132H: Positive (mutated)
ATRX: Lost (mutated)
p53: Positive
p16 CDKN2A: Patchy staining
MTAP: Intact
Ki67: Less than 10%
Final diagnosis
Astrocytoma, IDH-mutant, CNS WHO grade 2.
Unable to process the form. Check for errors and try again.