Table 2.
Challenges during menigioma management and recent study results on how to overcome them
| CHALLENGE | Diagnostic Approach | |
|---|---|---|
| Differential diagnosis | MRI |
Standard MRI—tumor location might be helpful (Table 1) MR perfusion14 ,26 to differentiate between meningioma and dural metastases, CAVE— tumors with elevated blood perfusion MRS peak at 3.8 ppm in meningiomas.30 |
| PET | - | |
| Neuropathology | STAT6 staining 31–34 to differentiate between meningioma and solitary fibrous tumor/ hemangiopericytoma | |
| Subtyping and grading | MRI |
Anatomical features
41
to distinguish between WHO grades Contradictory results on DW-MRI42 ,43 and perfusion MRI17 for meningioma subtyping |
| PET | Dynamic 18 F-FET PET 44 to distinguish between high-grade and low-grade meningiomas | |
| Neuropathology |
Histological features
4
: brain invasion as new additional criterion to diagnose atypical meningioma WHO grade II Molecular pathology62–67 : -AKT1/TRAF7 and SMO mutations mostly in basal meningioma with meningothelial histology -KLF4/TRAF7 mutation in secretory meningiomas WHO grade I |
|
| Assessment of tumor growth and risk of recurrence | MRI |
Follow-up imaging according to WHO grade
2
-WHO grade I: 1x/year for 5 years, afterward every 2 years -WHO grade II: every 6 months for 5 years, afterward 1x/year -WHO grade III: every 3–6 months indefinitely |
| PET |
68
Ga-DOTATATE PET
75
: SUVmax predicts faster growth in WHO grade I and II meningioma, not in WHO grade III 11C-MET PET76 ,77 : contradictory results on predicting tumor growth |
|
| Neuropathology | TERT promoter region mutation 3 , 68 , 69 is associated with increased risk of recurrence and shorter progression-free survival, present in only 6%–8% of meningiomas | |
| Delineation of tumor extent | MRI | Standard MRI has difficulties in differentiating meningioma from adjacent anatomical structures (skull base) and postoperative changes. |
| PET | 68 Ga-DOTATATE PET 10 to discriminate meningioma from tumor-free tissue uptake (SUVmax threshold, 2.3) and to improve target volume definition in radiation planning8 ,82–84 in the vicinity of bony skull base or after complex surgical procedures | |
| Neuropathology | Histological assessment of dura invasion and of other surrounding structures. | |
Abbreviations: ADC = apparent diffusion coefficient, MRS = magnetic resonance spectroscopy, ppm = parts per million, STAT6 = signal transducer and activator of transcription 6, 18F-FET = O-(2-[18F]-fluoro-ethyl)-L-tyrosine, 11C-MET = [11C]Methionine,68 Ga-DOTATATE = DOTA-(Tyr3)-octreotide, TERT = telomerase reverse transcriptase. SUV = standardized uptake value.