Rhabdoid meningioma is a rare and aggressive subtype of meningioma. Rhabdoid morphology is associated with a poor prognosis, regardless of tumour histogenesis. It resembles other types of rhabdoid tumours with a great tendency for recurrence 1,2. Extensive necrosis in rhabdoid meningioma might be indicative of an additional predictor of aggressive clinical behaviour 3.
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Epidemiology
It occurs in middle-aged individuals approximately 10 years earlier than typical meningioma. Like benign meningioma, there is a slightly increased predominance in females and in African Americans 2.
Clinical presentation
The presentation depends on the location of the lesion. Headache, seizures, visual manifestations, and focal neurological deficits have been described.
Pathology
The term rhabdoid morphology is referring to the characteristic resemblance of the cells to a rhabdomyoblast without true skeletal muscle differentiation. The term malignant rhabdoid tumour (MRT) was first used to describe a distinctive paediatric renal tumour, the term was applied to similar extra-renal paediatric tumours. Rhabdoid cells show abundant eosinophilic cytoplasm, cytoplasmic hyaline inclusions, and eccentric nuclei 4.
Grading
Generally, classified as WHO III malignant meningioma.
Radiographic features
Rhabdoid meningioma tends to have cystic and solid components with homogeneous enhancement of the solid component. There is extensive peri-tumoural oedema 2. Bone destruction, indistinct margins and central necrosis are known to correlate with aggressiveness.
MRI
Signal characteristics that correlate with aggressive behaviour of meningiomas include:
- T1: indistinct tumour border (saw teeth appearance of the margins) and marked mass effect
- T2/FLAIR: marked peri-tumoural oedema
- DWI/ADC: hyperintense signals on DWI that show restricted diffusion on ADC correlate with hypercellularity and more aggressive behaviour
- T1 C+ (Gd): avid enhancement that may extend into the bone if associated with bone destruction
- MR spectroscopy: an elevated level of alanine at short TE
Treatment and prognosis
The tumours have a tendency for recurrence and have a poor prognosis.