Ectopic orbital meningioma: Fact or fiction?

Primary intraorbital ectopic meningiomas are rare and their existence remains controversial. We present a 30-year-old female with painless, non-axial proptosis and a palpable superomedial mass. The MRI demonstrated that the mass had no optic nerve sheath or sphenoid wing involvement and was initially reported to have no intracranial extension. The patient was initially thought to have an ectopic orbital meningioma. Subsequent multidisciplinary team (MDT) consultation and further specialist review of the MRI revealed a subtle dural tail connecting to an enhancing mass in the olfactory groove. Biopsy revealed a WHO Grade 1 transitional meningioma with an infiltrative pattern. We argue that some previously reported cases of ectopic meningioma may lack the requisite imaging to discover the primary disease. Our report highlights the importance of MRI in this group of patients and the role of a skull-base MDT with specialist neuroradiology input to determine the true origin and extent of these extradural orbital meningiomas.