En plaque meningioma of the temporal bone: A systematic review on the imaging and management of a rare tumor.

Objective: To review the published cases of meningioma en plaque of the temporal bone (TB-MEP), to gather evidence on the clinical assessment and management of this rare entity.

Methods: Following PRISMA statement recommendations, 383 abstracts were screened independently by two authors. Inclusion criteria were articles of human patients affected by TB-MEP; English or Italian language; availability of the abstract articles unrelated to TB-MEP, guidelines and systematic reviews were excluded. Only full-text articles reporting the diagnostic work-up and the management of the TB-MEP were considered for analysis.

Results: A total of 12 articles were included, for a total of 25 patients with a mean age of 52 years (range: 31-71). The average time elapsed between the onset of symptoms and the actual diagnosis of TB-MEP was 36.5 months (range: 2-120). In most cases, the pathology presented with hearing loss (80 %), often accompanied by effusive otitis media (52 %), aural fullness (32 %), and tinnitus (32 %). The main Computed Tomography (CT) findings were hyperostosis (76 %), hairy appearance of bony margins (16 %), involvement of the mastoid and middle ear (48 %). Magnetic Resonance Imaging (MRI) revealed dural enhancement (28 %), temporal hyperostosis (20 %), a clearly enhancing extra-axial mass (28 %), compression of the surrounding vasculo-nervous structures (8 %) and the possible involvement of the temporal lobe (8 %). Forty percent of patients underwent various medical and surgical treatment before reaching the diagnosis. Forty-four percent of patients were sent to definitive surgical treatment, 44 % to follow-up while 8 % received radiotherapy.

Conclusions: Meningioma en plaque (MEP) is a rare tumour, particularly when it originates within the temporal bone. Appropriate imaging in patients complaining of audiological sign and symptoms is mandatory to avoid diagnostic delays, avoid inappropriate surgical procedures, and adopt the appropriate treatment.