Ancient schwannoma of the orbit

Orbital schwannoma management: a case report, literature review, and potential paradigm shift

PURPOSE

To present a case of orbital schwannoma and assess the literature on treatment modalities.

METHODS

A MEDLINE literature search for cases of orbital schwannomas was performed using the PubMed search tool using the search terms "orbital schwannoma" and "orbital neurilemmoma." Papers were included if they were peer-reviewed, published in English, discussed management, and included the search terms. Each article was rated using the scale developed by the British Centre for Evidence-Based Medicine. In addition, we present a case report of an orbital schwannoma.

RESULTS

A total of 428 articles were found. 102 met the criteria for inclusion. Only two articles met Level 1 evidence and 16 were important to the clinical care process. We report a case of a biopsy-proven orbital schwannoma managed conservatively with observation over a 4-year period due to risk of cosmetic disfigurement with tumor removal. There has been no change in tumor size and no associated complications during follow up.

CONCLUSIONS

There is a paucity of data on the natural history of orbital schwannomas. Based on our review of the literature, we recommend observation for asymptomatic or minimally symptomatic orbital schwannomas with minimal growth over an extended period of time. For rapidly growing tumors or large tumors affecting key structures causing visual loss, diplopia, aesthetic disfigurement, or patient discomfort, a more aggressive approach may be necessary.

An Unusual Differential Diagnosis of Orbital Cavernous Hemangioma: Ancient Schwannoma

Schwannomas are rare lesions of the orbit that can be confused with cavernous hemangioma on imaging studies. We report the case of an 84-year-old woman with a 9-year history of a tumoral lesion in the inferolateral left orbit. The imaging studies did not reveal specific characteristics, only bone remodeling due to the long evolution of the tumor. The patient underwent complete excision of the tumor by anterior orbitotomy via the inferior conjunctival fornix. The histopathological examination revealed an ancient schwannoma, a variant of schwannoma with uncommon histological features. The follow-up was uneventful. The present case emphasizes the importance of considering neural tumors in the differential diagnosis of orbital masses with bone changes and degenerative alterations such as hemorrhagic areas, cysts, and/or calcifications.

Ancient schwannoma of the orbit

The ancient schwannoma is a rare variant of a neurilemoma with a course typical of a slow-growing benign neoplasm. Histologically, it can be confused with a malignant mesenchymal tumor because of increased cellularity, nuclear pleomorphism, and hyperchromatism. Despite the degree of nuclear atypia, mitotic figures are absent. We describe the clinical and histopathologic features of an ancient schwannoma of the orbit. A need for early removal of such tumors is recommended to prevent complications.

A patient with swelling of the eyelid: ancient schwannoma of the supraorbital nerve (2010:6b)

We present a case of swelling of the eyelid and supraorbital anesthesia caused by an intraorbital tumor. The differential diagnosis based on imaging consisted of aneurysmal bone cyst, schwannoma, neurofibroma, dermoid cyst, and cavernous hemangioma. The surgical and pathological diagnosis was an ancient schwannoma of the orbit, a rare entity.

Bilateral Simultaneous Ancient Schwannomas of the Orbit

An unusual case of purely cystic bilateral ancient schwannomas of the orbit is reported. Complete ophthalmologic examination and CT was performed. Diagnosis was established by excisional biopsy of both tumors, including clinicopathologic study. Histologic examination showed a bilateral purely cystic ancient schwannoma. This case underlines the importance of considering neural tumors, including schwannomas, in the differential diagnosis of both cystic and bilateral orbital tumors. As far as we know, no other case has been previously reported.

Das „ancient schwannoma“

"Ancient schwannomas" of the mouth floor are rare, benign neoplasms derived from the nerve sheath of peripheral nerves. They show many degenerative changes such as necrosis and vascular thrombosis. Ancient schwannomas show histopathological features, such as degenerative changes and atypical nuclei, and may easily be confused with malignant neoplasms. B-scan sonography for the mouth floor and MRT imaging may be helpful in differential diagnosis. Here, we report on a patient with ancient schwannoma of the floor of the mouth.

Ancient schwannoma of the parotid gland: a case report and review of the literature

Schwannomas are encapsulated benign tumours arising from nerve sheath cells, of which ancient schwannoma is one of five variants. Since the first description, only a few ancient schwannomas have been reported in different locations in the head and neck region. In the parotid gland, this tumour is very rare. In this report, a 41-year-old female patient with an ancient schwannoma of the parotid gland is presented and the data of this patient compared with other (comparable) cases described in the literature.

Trigeminal nerve schwannoma with ancient change. Case report and review of the literature

Ancient change in a schwannoma is a histological variant typically found in longstanding tumors. Histologically, the tumor has biphasic features typical of a schwannoma with evidence of degenerative changes that may complicate diagnosis. The authors report on a 23-year-old man with no features of neurofibromatosis who presented with headaches, blurred vision, and ataxic gait. Magnetic resonance imaging demonstrated a rim-enhancing lesion in the cerebellopontine angle with displacement of brainstem structures and no supratentorial hydrocephalus. Using a lateral suboccipital approach together with image guidance and intraoperative neurophysiological monitoring, a gross-total macroscopic excision was performed. At surgery, the tumor was found to arise from the inferior division of the trigeminal nerve. The final histological diagnosis was schwannoma with ancient change. Note that ancient change in schwannomas is a histological variant thought to result from degenerative changes in longstanding tumors. To the authors' knowledge, this is the first independent report of this histological variant in an intracranial schwannoma.

Orbital Schwannoma and Neurofibroma: Role of Imaging

Schwannomas are well-circumscribed ovoid masses that most commonly present in the superior orbit. Although it may be difficult to differentiate these benign masses from other orbital tumors on radiologic imaging, the CT and, in particular, the MR imaging characteristics can sometimes point to the diagnosis of a nerve sheath tumor. A definitive diagnosis can be made through correlation with histopathologic findings, however. In most cases, schwannomas have low malignant potential, and with total excision, recurrence is rare.

'Ancient' schwannoma of the orbit

A 65-year-old woman presented with a 3 month history of right eye discomfort and protrusion. Examination revealed right proptosis with hypoglobus and diplopia in extremes of upgaze. Computed tomographic scanning revealed a large extraconal mass in the superotemporal orbit. The mass was excised through an extended superior skin crease incision. Histopathology revealed a benign tumour of Schwann cell origin showing advanced cystic degeneration, the so-called 'ancient schwannoma'. The authors could find only two previously reported cases of such tumours arising in the orbit.

Neural orbital tumors

Primary tumors of the optic nerve (optic nerve sheath meningiomas and optic nerve astrocytomas) are important causes of visual morbidity. They may elude clinical detection and have the potential to be lethal. Their treatment remains controversial but often includes radiation. The optic nerve may be involved secondarily by peripheral nerve tumors in the orbit or by metastatic and infiltrative neoplasms. Optic neuropathy may also develop as a result of treatment of these tumors. Recent contributions to the literature concerning the diagnosis and management of neural orbital tumors are reviewed.