Ectopic orbital meningioma: a retrospective case series

Primary ectopic meningiomas: Report of 6 cases with emphasis on atypical morphology and exploratory immunohistochemistry

AIMS

To investigate the histological and immunohistochemical features of primary ectopic meningiomas (PEMs), especially those of primary ectopic atypical meningiomas (PEAMs).

METHODS AND RESULTS

We examined 6 cases of PEM, including 2 PEAM cases, which occurred separately in left nasal cavity, left lower lung, right neck, left orbit, right upper lung, and left upper lung by histological and immunohistochemical analysis. In general, of the 6 PEM cases analyzed, 4 cases exhibited morphology of Grade Ⅰ, including 1 fibrous, 1 meningothelial, and 2 transitional variant. The remaining 2 cases shared similar atypical morphology of Grade Ⅱ. The tumors were distributed in sheet-like patterns with loss of architecture of classic meningiomas. Significant hypercellularity, multi-focal necrosis, and thin-walled blood vessels were identified. The mitotic figures were estimated at 6 per 10 high-power fields in one case, and 8 mitotic figures in another. Immunohistochemically, the 6 PEM cases were all positive for Vimentin and EMA, while none showed immunostaining for CKpan, S-100, CD34, STAT6, SMA, Syn or Bcl-2. 4 PEM cases of Grade Ⅰ were immunoreactive for PR but negative for P53, while the 2 PEAM cases displayed negative staining for PR but positivity for P53. As for Ki-67, the positive staining of 4 Grade Ⅰ cases was no greater than 2%, while the positive rates of the 2 PEAM cases were 10% and 20%.

CONCLUSIONS

Our study has expanded cases of PEMs, especially the 2 PEAM cases in rare sites. Our study has also further summarized the pathological features of PEMs, focusing on the histological features of PEAMs, and the immunohistochemical features worthy of further investigations.

The use of an endoscopic endonasal approach for a secondary intraorbital meningioma: illustrative case

BACKGROUND

Meningiomas are the most frequent primary tumors in the central nervous system (CNS), but intraorbital location is uncommon and accounts for only 0.2% to 4% of all CNS meningiomas. Lesions in this compartment could be classified as primary, secondary, or ectopic. The close relationship with the optic nerve sheath is a landmark to identify the tumor as primary, whereas secondary tumors commonly come from an extension of an intracranial meningioma, and ectopic meningioma is a concept not yet completely established.

OBSERVATIONS

The authors present a rare case of a secondary intraorbital meningioma operated through an endoscopic endonasal approach. Secondary meningiomas at the medial orbit are very uncommon, given their more common superior and lateral location as an extension of sphenoid meningiomas. The endoscopic endonasal route provides direct access to the medial orbit. The authors present an illustrative case of a meningioma located at the medial orbit and resected through an endoscopic endonasal approach that provided excellent visualization and anatomical exposure. Additionally, the authors review the concept and possible similarities between secondary and ectopic intraorbital meningiomas.

LESSONS

An endoscopic endonasal approach should be considered as a feasible treatment option for intraorbital meningiomas, especially if they are in the medial orbital wall.

Primary Extradural Ectopic Orbital Meningioma in a Child

The authors describe a rare case of primary extradural ectopic meningioma of the orbit in a 13-year-old female managed with surgical excision, adding to the very limited literature of this diagnosis in children. This is the second case to show a radiological abnormality in the gyrus rectus and olfactory bulb; however, in our case, there was no radiological evidence of connection seen.

Isolated Intraconal Meningioma

Purpose

To report a rare case of isolated intraconal meningioma.

Case Report

A 24-year-old woman presented with painless proptosis in her left eye which started and progressed during her pregnancy about 10 months ago. Hertel exophthalomometry revealed anterior displacement of the globe with 4 mm of proptosis which was remarkable. Magnetic resonance imaging (MRI) demonstrated an intraconal circumscribed oval-shaped mass with hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images, mimicking cavernous hemangioma. This mass, however, was free of any connections to optic nerve or bones. Due to the imaging characteristics, more prevalent diagnoses like cavernous hemangioma were placed on the top of the differential diagnoses list. However, during the surgical excision, the tumor’s consistency and gross features were not compatible with cavernous hemangioma. The pathologic findings instead determined meningotheliomatous meningioma, a very rare condition, which was far from our expectations prior to the surgery.

Conclusion

Ectopic orbital meningiomas are rare tumors that are not easily diagnosed without postoperative histopathology. Despite its low prevalence, they should be considered in the differential diagnosis list of intraconal masses with hypointense signals on T1-weighted images and hyperintense signals on T2-weighted images.

Ectopic intraconal orbital meningioma - A rare case report

Background

Ectopic orbital meningiomas (OM) are a rare subset of OMs which are neither attached to the optic nerve sheath nor to the surrounding bone.

Case Description

We report the case of a 65-year-old female who presented with a 1 year history of proptosis followed by visual loss and restricted right eye movements since 3 months. Radiology of the orbits was suggestive of intraorbital, intraconal, and heterogeneous contrast enhancing right eye lesion which was completely excised through supraorbital orbitotomy approach. Intraoperatively, the right optic nerve, though compressed, and displaced inferiorly, was free from the lesion. The final histopathological diagnosis was "Meningioma WHO Grade I." At 3 months follow-up, patient's vision in the right eye improved from perception of light positive to 6/12 and there was no evidence of recurrence.

Conclusion

Rarity of ectopic OM, total surgical excision with an excellent postoperative visual outcome prompted us to report this case.