Table 2.

IDH1‐mutant tumors originally diagnosed as ganglioglioma. Abbreviations: DOD = died of disease; WHO = World Health Organization.

Case	Age	Sex	WHO grade	Mitoses/hpf	Location	Outcome
1	74	Male	III	4/10	Right frontal	DOD 2.5 years later
2	51	Female	“Atypical features”	0/10	Left parietal	Recurrence 4 years later with malignant transformation to GBM; DOD 1 year after recurrence
3	45	Male	“Atypical features”	1/10	Right temporal	Recurrence 6 years later diagnosed as grade II‐III astrocytoma, treated with temozolomide and radiation
4	45	Male	“Atypical features”	0/10	Left frontal	Postsurgical radiation, recurrence 5 years later, progression to grade III oligodendroglioma two years after initial recurrence; DOD 13 years after original diagnosis
5	52	Male	I	0/10	Frontal	Radiation after surgery, recurrence 15 years after initial diagnosis; no follow‐up information since then
6	20	Male	I	2/10	Left posterior frontal lobe	Recurrence 5 years after diagnosis, treated with radiation
7	44	Male	I	2/10	Not specified	Alive 8 years after surgery, no additional information available
8	38	Female	“Atypical features”	0/10	Right parietal	Residual/recurrent tumor within 1 year of surgery, treated with radiation

Eight of the 98 cases studied had IDH1 mutations; all were wild type for IDH2. Common features include advanced age and trends toward extratemporal location and mitoses. Most have already shown aggressive behavior.