Ectopic orbital meningioma: Fact or fiction?

Abstract

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.

Isolated Intraconal Meningioma

“…Having said that, other distinguished researchers continue to consider ectopic meningioma as a distinct entity where the origin and existence of ectopic orbital meningioma is still being debated. [12] To date, there have been few reports of intraconal ectopic meningioma cases. A brief review of some of the recent reports of ectopic meningioma cases and other related issues such as demographic data, history, imaging findings, treatment, and final outcomes are summarized in Table 1.…”

Primary Extradural Ectopic Orbital Meningioma in a Child

“…Tan et al 11 described a similar case to our case, where an enhancing mass was noted in the olfactory groove on MRI; however, it was felt to be connected via a dural tail to the orbital lesion. 11 They postulated that other reported cases of “ectopic” orbital meningiomas may have instead arisen from the olfactory groove and the importance of MRI and specialist neuroradiology opinion in the diagnostic work-up. 11 Our case was reviewed in a multidisciplinary team setting with neuroradiologists who did not consider the 2 lesions to be contiguous, and furthermore on the imaging 18 months prior, there was no evidence of any lesion in the gyrus rectus or olfactory groove.…”

Primary extradural ectopic orbital Meningioma.

“…Meningiomas are one of the most frequent neoplasms arising from the meninges. These tumors belong to the arachnoid villi structures [3]. Commonly, meningiomas are attached to the dura and grow in the cranial cavity or intraspinal region.…”