ORBITAL PATHOLOGIES

Dr. Mohit GoelJR III

3/07/2014

1. Congenital anomalies

2. Infection / Inflammation

3. Tumors

4. Trauma

5. Neoplasm

Congenital anomalies

MIcropthalmia

Pthisis Bulbi

Coloboma

Colobomatous cyst

Ocular detachments

Retinal detachment.

Inflammatory conditions

Optic neuritis

Acute inflammation of optic nerve , commonly associated with multiple sclerosis.

Edema and inflammatory cells infiltrate the nerve resulting in uniform swelling and focal demyelination.

Imaging : MRI is the modality of choice with hyper intense signal of T2WI due to fluid and edema. Fat Sat contrast enhanced T1WI will show

areas of demyelination. CT relatively insensitive.

Straightening and thickening of right optic nerve.

Optic Neuritis. CE Fat Sat T1W axial(B) MR images demonstrate subtle enlargement and enhancement of the left

optic nerve (curved arrow). T 2 WI (C) demonstrates corresponding increased signal intensity (straight

arrow).

Retinoblastoma

Retinopathy of Prematurity

Coat’s disease

Primary retinal telengiectasis Vascular anomaly of retina Characterized by idiopathic retinal

telengiectatic and aneurysmal retinal vessels Progressive deposition of intraretinal and

subretinal exudates Leads to massive exudative retinal detachment

Ocular astrocytic Hamartoma

Benign yellow-white rare retinal tumor Associated with Tuberous Sclerosis or

Neurofibromatosis Early on it may look exactly like retinoblastoma May involve retina or optic nerve

Juvenile Xanthogranuloma

Benign cutaneous disorder Affects eye and skin Affects iris and ciliary body, choroid, retina and

optic nerve May present as a solitary orbital mass

Optic nerve head drusen

Tumors

Choroidal osteoma

Benign tumor Unilateral usually Affects young white girls Patients present with painless progressive loss

of vision

Malignant uveal melanoma

More common in whites May arise from pre-existing nevi Metastasizes hematogeneously to liver

Orbital Pseudotumor• The most common cause of orbital mass in adults. • Acute form presents with pain, proptosis and

diminished ocular mobility, with histological changes similar to vasculitis.

• Chronic form may mimic infection or lymphoma both clinically and histologically. Unilateral presentation is most common, but findings can be bilateral. All compartments of the orbit may be affected.

• Imaging -- Heterogeneous poorly marginated increased CT density and decreased T1 & T2 MRI signal intensity within the intraconal fat surrounding a thickened sclera or enlarged optic nerve, sometimes simulating a mass.

• The lacrimal gland may be enlarged. Enhancement occurs following contrast infusion.

Fig A. Scleral pseudotumour. Marked thickening and irregularity of the sclera of the right globe involves the adjacent retro-orbital fat.Fig B. Diffuse pseudotumour. Axial MR T1WI showing a diffuse mass in the right orbit due to pseudotumour.

Rhabdomyosarcoma• Rhabdomyosarcoma is the most common primary

orbital malignancy in the pediatric age group. with most patients presenting below 6 years of age.

• Patients present with rapidly progressive exophthalmos that may mimic orbital infection. Spread of the tumor esp. intracranially, portends poor prognosis.

• Imaging : Both CT and MRI will typically show a mass involving an extra ocular muscle. Lesions are isodense on CT and isointense on T1WI when compared to muscle.

• There may be associated bony destruction and contiguous extra orbital spread. The tumor involves the globe less often. Marked enhancement throughout the mass is seen after contrast administration.

Rhabdomyosarcoma. CECT image

(A) Orbits demonstrates right proptosis due to large, lobular, intraorbital mass.

(B) Image at lower level demonstrates invasion of right maxillarysinus (asterisk) as well as extension through lateral orbital wall (arrow),

consistent with the aggressive nature of this tumor.

Optic nerve sheath complex

• Patients with abnormalities of the optic nerve and its covering present with proptosis, visual loss and papilloedema.

• Expansion of the tubular shaped optic nerve and sheath is well demonstrated on CT and MRI.

• Imaging of the intracranial space is required because the optic nerve and its coverings are continuous with the brain and dura mater.

Optic nerve Glioma:

Occur in childrenAre low grade astrocytomas.

Associated with NF-1Imaging:- optic nerve may expand uniformly and diffusely. Plain

films will show asymmetric widening of the optic canal. Post contrast show uniform enhancement.

Optic nerve glioma.

Enhanced coronal CT image demonstrates homogeneous

enhancement of enlarged right optic nerve.

Optic nerve glioma. Enhanced fat-saturated axial T1W image (A) demonstrates mild enhancement and enlargement of intraorbital

and canalicular segments of left optic nerve.Coronal image (B) confirms enlargement of nerve and surrounding perioptic

space.

Optic nerve meningioma

• Meningiomas are dense fibrous tumors. Calcification is common.

• Plain films may show widening of the optic canal, or hyperostosis of the sphenoid wing.

• CT generally shows a dense, sharply defined tubular mass surrounding and paralleling the course of the optic nerve, with marked enhancement after contrast administration ('tram track'). Kinking of the nerve may be seen.

• MRI will show a homogeneous mass of decreased T1 and T2 signal intensity, with strong enhancement, especially with the use of fat suppression sequences.

• Coronal images are preferred, as the encased optic nerve will be seen in relief against the densely enhanced tumor.

Fig A. Optic nerve Meningiomas. CT -- Enhancement of thickened rightoptic nerve with elevation of optic disc (arrowhead).

Fig B. Axial T1-weighted post contrast fat-saturated image (B) demonstrates peripheral enhancement of the thickened right optic nerve sheath.

Nonenhancing soft tissue within represents the encased optic nerve.

Trauma

Miscellaneous

Thyroid ophthalmopathy. Unenhanced axial (A) and coronal (B) CT images demonstrate massive

enlargement of the rectus muscles, including fusiform enlargement of the lateral rectus with relative sparing of the distal muscle insertion.

Lymphoma. T1WI (A) demonstrates proptosis of right globe due to a large intermediate signal intensity lesion that involves the lacrimal fossa and the

right lateral rectus muscle (arrow), with extension posteriorly in the extraconal compartment.

Post contrast image (B) demonstrates homogeneous enhancement.

Cavernous Hemangioma. T1-weighted axial (A) and sagittal (B) MR images demonstrate proptosis of right globe due

to well circumscribed, mid to high signal intensity intraconal mass.

Lymphangioma. Axial T,-weighted (A) and T2 -weighted (B) MR images demonstrate mild right

proptosis due to complex, multi loculated, cystic, extra-axial lesion in the superomedial aspect of the right orbit.

Encephalocele. Axial T1W MR image demonstrates marked proptosis of right globe with stretching of attenuated right optic nerve (arrowhead) due to herniation of dura and temporal lobe

through a large sphenoid defect in this patient with neurofibromatosis.

Non-plexi form neurofibromas and neurinomas are ovoid, well defined,homogeneous and hypovascular, with mild uniform enhancement.

Cystic degeneration may occur, and will appear hypodense on CT, and hyperintense on T2W MR sequences.

Plexiform neurofibromas are poorly defined, crossing fascial planes and surrounding normal structures.

Plexiform neurofibroma. T1WI(A) and T2WI (B) MR images show extensive left temporal scalp lesion with extension to left orbit resulting in mild

proptosis. MR also demonstrates ectatic left optic nerve (arrow). CT image at bone windows (C) demonstrates associated bony defect of left

lamdoid suture.

MetastasisMetastases to the orbit may occur from systemic primaries,

particularly neuroblastoma and leukaemias in children, and breast, lung, prostate and stomach cancer in adults. These lesions are poorly defined,

infiltrative and demonstrate marked contrast enhancementon CT and MRI.

Prostatic Ca: Axial CT (A) shows small lytic lesion of left lateral orbital wall. Soft-tissue windows (B) demonstrate contiguous extension of soft tissue into

lateral extraconal compartment (asterisk) with medial displacement of the lateral rectus muscle.

Dermoid / Epidermoid

These are congenital lesions that result from sequestration of primitive ectoderm in the region of the orbit, usually presenting during childhood as a

discrete mass, located near the lacrimal fossa or nasal bone and are homogeneous in appearance. The presence of fat is clearly seen on CT and

MRI. They do not enhance.

Lacrimal gland dermoid. Coronal T 1WI demonstrate a well-circumscribed lesion located in the upper outer quadrant of left orbit.

High signal intensity is consistent with fat.

Thank You