Pus between orbital wall and periosteum

Almost always associated with sinusitis

Anywhere in orbit, especially adjacent to ethmoid sinusitis

Brain MR if intracranial complication of sinusitis suspected

Lentiform, rim-enhancing extraconal fluid collection (phlegmon or abscess)

± air-fluid level = drainable pus

Usually with preseptal cellulitis and deviation of extraocular muscle (EOM)

± edematous intraconal or extraconal fat, enlargement of EOMs (myositis)

Vascular neoplasm, NOT malformation

Not well seen at birth; more apparent within 1st few weeks of life

Proliferating phase: 1st year

Involuting phase: 1-5 years

Involuted phase: 5-7 years

GLUT-1: Specific immunohistochemical marker expressed in all 3 phases of infantile hemangioma

Congenital hemangioma: Rare variant, present at or before birth

2 subtypes of congenital hemangioma = rapidly involuting (RICH) and noninvoluting (NICH)

RICH shows involution by 8-14 months

Proliferating phase: Solid, intensely enhancing mass with high-flow vessels

Involuting phase: Fat infiltration, ↓ size

May be part of PHACES syndrome: Posterior fossa abnormalities, hemangiomas, arterial anomalies, cardiovascular defects, eye abnormalities, sternal clefts

Congenital vascular malformation

Lymphatic channels of varying sizes

Present at birth, grows with child

Hemorrhage or respiratory infection causes sudden ↑ in size with resultant rapidly developing proptosis

Intracranial vascular anomalies present in ˜ 2/3 of patients with periorbital lymphatic malformation

Uni- or multilocular; macrocystic or microcystic

Intra- ± extraconal location

Only septations enhance, unless mixed venolymphatic malformation

Fluid-fluid levels best seen on MR

Metallic foreign bodies (FB) most dense

Glass more dense than bone

Wood: Very low density (˜ air density) → soft tissue density as it resorbs serum

Living plant material ˜ soft tissue density

FB, bone fragments, &/or adjacent hematoma proptosis

± globe rupture, intraocular FB, intracranial injury

Benign inflammatory process with fibrosis painful proptosis

Myositic: Most common subtype

Diffuse enlargement and enhancement of EOMs, including tendinous insertions

Lacrimal: Enlargement and enhancement

Anterior: Thickening and enhancement of sclera ± choroid, ± involvement of retrobulbar fat, nerve, or sheath

Diffuse: Intra- ± extraconal, may be mass-like, usually without globe deformity or bone erosion

Apical: Enhancing orbital apex mass, extension through fissures

H&N sites: Orbit, parameningeal (middle ear, paranasal sinus, nasopharynx), and all other H&N sites

Soft tissue mass, variable enhancement

± bone erosion

± intracranial or sinus extension

Most common malignant tumor in children < 1 year of age

Majority of primary tumors retroperitoneal adrenal origin

Soft tissue mass + aggressive bone erosion and spiculated periosteal reaction

When bilateral, frequently involves lateral orbital walls

± intracranial extension

In H&N: Orbit, maxilla, mandible, temporal bone, cervical spine, skull

Enhancing soft tissue mass with smooth osseous erosion

Includes NHL and lymphoid hyperplasia (benign polyclonal reactive hyperplasia and indeterminate atypical hyperplasia)

Diffuse or focal masses

Homogeneous enhancing soft tissue mass anywhere in orbit

Direct fistula between cavernous ICA and cavernous sinus

Secondary to trauma, venous thrombosis, or aneurysm

Proptosis + large superior ophthalmic vein, cavernous sinus, and EOMs

“Dirty” orbital fat related to edema