Ординатура / Офтальмология / Английские материалы / Rapid Diagnosis in Ophthalmology Series Oculoplastic and Reconstructive Surgery_Nerad, Carter, Alford_2008

Neoplasms• 11 SECTIONOrbit: the of Disorders

Optic Nerve Meningioma

Key Facts

•Benign tumor of optic nerve meninges

•Occurs most commonly in women in third to fourth decades

•Vision loss occurs from growth of tumor within meninges compressing the optic nerve

Clinical Findings

•Gradual unilateral visual loss over years

•Relative afferent pupillary defect on affected side

•Slow, painless, progressive proptosis, but proptosis is usually a late sign (Fig. 11.21)

•Optic nerve head may be normal, swollen, or atrophic

•Collateral vessels (optociliary) may be present

•Bilateral optic nerve meningiomas (rare) associated with neurofibromatosis type 1

•Tumor contains whorls, or clusters, of meningothelial cells that fill the subarachnoid space and can compress the nerve

•Psammoma bodies (responsible for calcification on CT scan) may be present

•Tumor can extend through the dura.

Ancillary Testing

•CT:

• optic nerve enlargement, either localized or fusiform

•classic railroad track sign may be present, caused by calcification of the

tumor in the subarachnoid space (diagnostic, but occurs in a minority of cases) (Fig. 11.22)

•MRI:

•to determine posterior extent of tumor

•T1 isointense, T2 bright, enhances with gadolinium (Fig. 11.23)

Differential Diagnosis

•Optic nerve glioma if tumor present in fusiform pattern

• Glioma more common in children

•Rarely, other optic nerve infiltrations; sarcoidosis or lymphoma

Treatment

•Observation if the tumor is anterior and vision is good, serial examinations and scans

•Radiation if vision worsens to 20/60, with hope of slowing growth

•Surgical excision if shows posterior extension into optic canal prechiasmal region

• Transcranial approach resecting tumor from chiasm to globe

•“Stripping” tumor from optic nerve incompletely removes tumor and leaves the eye blind by devascularizing the nerve

Prognosis

•Preservation of vision over long periods because of the slow growth of tumor

•Radiation has been shown to slow tumor growth and vision loss

•Surgical treatment results in blindness and should be reserved for cases with poor vision or intracranial extension

Neoplasms• 11 SECTIONOrbit: the of Disorders

Sphenoid Wing Meningioma

Key Facts

•Benign neoplasm arising from meninges

•Secondary orbital tumor entering orbit through:

•superior orbital fissure

•inferior orbital fissure

•optic canal

•Apical compression can damage vision

•On imaging, hyperostosis of sphenoid wing is characteristic

Clinical Findings

•Slowly progressive proptosis from bone thickening or orbital extension of tumor

•Fullness of temple from tumor expansion of sphenoid wing

•Normal vision but can experience optic nerve compression with gradual visual loss and visual field changes

•Diplopia possible with orbital invasion or restriction of lateral rectus muscle (Fig. 11.24)

Ancillary Testing

•CT shows bony changes in sphenoid wing (hyperostosis)

• Tumor extension into orbit can be seen also (Figs 11.24–11.26)

•MRI shows enhancement of tumor with gadolinium

•Useful to determine intracranial extent of tumor, especially along the dura that appears as a tail from the main tumor

•Visual field changes can occur without visual acuity loss, from slow progressive optic nerve compression

Differential Diagnosis

•Osteoma

•Fibrous dysplasia

•Ossifying fibroma

Fig. 11.24 A 35-year-old woman with left periocular swelling. Axial CT shows hyperostosis of the right sphenoid bone. Note the lateral rectus being pushed medially.

Fig. 11.25 Coronal CT bone window shows a thickened sphenoid bone. The tumor is decreasing the size of the posterior orbit. Optic nerve compression is possible.

Meningioma Wing Sphenoid

Neoplasms• 11 SECTIONOrbit: the of Disorders

Sphenoid Wing Meningioma (Continued)

Treatment

•Observation appropriate for patients with small non-progressive tumors

•If vision is affected or growth documented, transcranial resection of the tumor, usually including optic canal decompression, is recommended

•Tumor removal is usually incomplete, because preservation of the function of cranial nerve function is a priority (Fig. 11.26)

•Reconstruction of large orbital roof defects will prevent pulsating exophthalmos

•Radiation therapy after debulking decreases recurrence rate

•Radiation therapy alone may be suitable for elderly patients

•Hormone therapy or chemotherapy generally not useful

Prognosis

•Recurrence of complex incompletely removed tumors occurs over decades

•More localized tumors may be cured

•Risk of malignant transformation extremely small

Neoplasms• 11 SECTIONOrbit: the of Disorders

Rhabdomyosarcoma

Key Facts

•Most common primary orbital malignancy in children

•Primitive soft tissue tumor of mesenchymal origin

•Rhabdomyosarcoma can occur anywhere in body, but in children occurs most commonly in head and neck

•Although uncommon, diagnosis should be considered in any child with rapidly progressive proptosis

Clinical Findings

•Progressive proptosis in a child, occurring over days to weeks

•Average age is 7.5 years but can occur from birth to late in life

•Diagnosis usually delayed several weeks after onset of signs, with parents attributing the proptosis to minor trauma

•Proptosis can be axial or non-axial depending on position and size of tumor (Figs 11.27 and 11.28)

• Superonasal quadrant is most common location for the tumor

•Inflammatory signs usually absent

Ancillary Testing

•CT of orbit to characterize tumor

•MRI useful to visualize tumor originating outside but extending into orbit (secondary orbital tumor)

•Imaging may show well-demarcated mass isolated to orbit or destructive lesion extending into orbit (Fig. 11.27B)

A

B

Fig. 11.27 Orbital rhabdomyosarcoma. (A) Proptosis and upward displacement of the globe due to inferior mass. (B) Coronal CT scan showing well-circumscribed inferior orbital mass without bone erosion.

Rhabdomyosarcoma

Neoplasms• 11 SECTIONOrbit: the of Disorders

Rhabdomyosarcoma (Continued)

•Incisional biopsy (Fig. 11.28B):

•send specimens for routine histopathology and immunochemical stains

•cross-striations (muscle differentiation) are seen in less than half of tumors

•Additional tissue may be sent for electron microscopy or genetic studies (possible mutation in p53 tumor suppressor gene on chromosome 17p13)

•Four histologic subtypes:

1.embryonal (most common)

2.alveolar (worst prognosis)

3.pleomorphic (rare in orbit)

4.botryoid (only in conjunctiva)

•Neck node palpation

• CT and MRI of head and neck

•Systemic work-up to rule out metastatic disease

Differential Diagnosis

•Bacterial orbital cellulitis

•Lymphangioma

•Metastatic tumor:

•neuroblastoma

•Ewing sarcoma

•Idiopathic orbital inflammatory disease

Treatment

•Biopsy for diagnosis and staging

•Chemotherapy and radiation (4000–4500 cGy)

•Complications of chemotherapy:

•bone marrow suppression

•cardiac toxicity

•respiratory distress

•metabolic abnormalities

•secondary malignancies

•Complications of radiation therapy:

•bone growth retardation

•dermatitis

•radiation retinopathy

•enophthalmos

•dry eye

•decreased vision

Prognosis

•5-year survival rate for isolated orbital rhabdomyosarcoma is 95%

•Orbital exenteration or other extensive surgery not indicated unless conventional therapy fails

A

B

Fig. 11.28 (A) Proptosis and ptosis due to superior and retrobulbar mass. (B) Anterior orbitotomy for incisional biopsy.

(continued) Rhabdomyosarcoma