rhabdoid meningioma

Rhabdoid meningioma is a rare and aggressive subtype of meningioma, it is classified as WHO grade III. Rhabdoid morphology is associated with a poor prognosis, regardless of tumor histogenesis. It resembles other types of rhabdoid tumors with a great tendency for recurrence. Extensive necrosis in rhabdoid meningioma might be indicative of an additional predictor of aggressive clinical behavior .

Epidemiology

It occurs in middle age group approximately 10 years earlier than typical meningioma. Like benign meningioma, there is a slightly increased predominance in females and in African Americans .

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 tumor (MRT) was first used to describe a distinctive pediatric renal tumor, the term was applied to similar extra-renal pediatric tumors. Rhabdoid cells show abundant eosinophilic cytoplasm, cytoplasmic hyaline inclusions, and eccentric nuclei .

Grading

Generally, classified as WHO III malignant meningioma.

Radiographic features

Rhabdoid meningioma tends to have cystic and solid components with homogenous enhancement of the solid component. There is extensive peri-tumoral edema . Bone destruction, indistinct margins and central necrosis are known to correlate with aggressiveness.

MRI

Signal characteristics that correlate with aggressive behavior of meningiomas include:

• T1: indistinct tumor border (saw teeth appearance of the margins) and marked mass effect
• T2/FLAIR: marked peri-tumuoral edema
• DWI/ADC: hyperintense signals on DWI that show restricted diffusion on ADC correlate with hypercellularity and more aggressive behavior
• 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 tumors have a tendency for recurrence and have a poor prognosis.

Siehe auch:

• Meningeom