Key points Definition: Squamous cell carcinoma (SCC) of the lacrimal sac is an uncommon but deadly cause of abnormal unilateral tearing, which when not promptly diagnosed and treated can lead to local invasion and death. Classic clue: A patient presents with unilateral epiphora (uncontrolled tearing with tears overflowing onto the face), recurrent dacryocystitis, and imaging showing a lacrimal sac mass. Imaging Computed tomography features Computed tomography…

Key points Definition: Adenoid cystic carcinoma of the lacrimal gland (ACC LG) is a rare form of adenocarcinoma causing an extraconal, unencapsulated malignancy, usually arising from the lacrimal gland’s orbital lobe. Synonym: cylindroma. Classic clue: A middle aged woman presents with diplopia, proptosis, pain, and paresthesia. An unencapsulated, irregular, ovoid, soft tissue lacrimal fossa mass is evident resulting in inferiomedial globe displacement with a heterogeneous T2…

Key points Definition: Lacrimal gland dermoids (LGDs) represent congenital, non-neoplastic choristomas, containing cytologically normal tissue not normally found at that location. Synonym: anterior orbital dermoid (AOD). Classic clue: Young child presents with smooth scalloping of orbital wall by adjacent unilateral lacrimal-gland mass having hyperdense wall, decreased attenuation center, increased T1 signal intensity, and no postcontrast enhancement. Imaging Computed tomography features LGDs are typically unilateral well-defined cyst-like…

Key points Definition: Malignant lymphoma of the lacrimal gland is relatively rare and is more prevalent in elderly women. Synonym: Primary lacrimal gland lymphoma. Classic clue: Patient presents with painless proptosis, showing nearly symmetrical bilateral lacrimal gland enlargement with smooth, homogeneous, diffuse enhancement and restricted diffusion. Despite being rare, lymphomas comprise 37% of lacrimal gland malignancies. Imaging Computed tomography features Bilateral lacrimal gland enlargement is isodense…

Key points Definition: Bilateral lacrimal gland enlargement secondary to sarcoidosis, a systemic idiopathic inflammatory granulomatous disease. Classic clue: Bilateral lacrimal gland enlargement in a patient with “dry-eye” symptoms and known (or findings consistent with) sarcoidosis. Despite decades of delving into this dire disease, its etiology remains unknown. Sarcoid’s ocular and orbital emergence may precede by decades the development of systemic symptoms. , Important for radiologists to…

Key points Definition: Infiltration of the optic nerve (ON) is a rare entity important to recognize in patients with leukemia, as early diagnosis and treatment are the only hope for prevention of blindness. Synonym: ON infiltration by leukemia. Classic clue: Enlarged ON with avid enhancement in patient with orbital discomfort and rapidly deteriorating vision. ON involved in 13% to 18% of all leukemic types. , Diagnosis…

Key points Definition: Optic nerve neuritis (ONN) is inflammation of the optic nerve (ON), which may cause sudden painful, partial or complete visual loss, for a variety of reasons. Classic clue: Young woman presenting with painful eye movement, decreased visual acuity showing enlarged, enhancing ON, and periventricular white matter lesions suggesting multiple sclerosis (MS). ONN usually develops in association with an autoimmune disorder, which may be…

Key points Definition: Idiopathic orbital pseudotumor (IOP) is a nonmalignant, nongranulomatous extraocular orbital and adnexal space-occupying lesion simulating neoplasm without associated local or systemic etiology. Synonyms: Idiopathic orbital inflammation (IOI), idiopathic orbital inflammatory disease, nonspecific orbital inflammation (NSOI). Classic clue: 45-year-old female presents with pain, proptosis, periorbital swelling, and decreased vision in one or both eyes. Imaging shows poorly circumscribed enhancing intraorbital soft tissue mass. Most…

Key points Definition: An autoimmune inflammatory disorder affecting the orbit with leukocytic infiltration causing erythema, edema, conjunctivitis, and upper lid retraction. Synonyms: Graves ophthalmopathy, thyroid orbitopathy, thyroid eye disease (TED), thyroid associated orbitopathy (TAO). Classic clue: Bilateral extraocular muscle (EOM) enlargement sparing tendinous insertions, with increased retroorbital fat and exophthalmos. Most common cause of proptosis in adults. Compression of optic nerve (ON) may cause optic neuropathy.…

Key points Definition: Optic disc drusen (ODD) are tiny yellow or white globules of hyaline-like material deposited on or below the surface of the optic disc, which progressively calcify producing visual field defects. Also known as optic nerve head drusen (ONHD), disc hyaline bodies, pseudopapilledema, pseudoneuritis, buried disc drusen, and congenitally elevated or anomalous discs. Classic clue: Small sharply circumscribed dense calcification at one or more…

Key points Definition: Cataracts cloud the normally clear ocular lens, block the passage of light to the retina, and cause decreased vision and blindness if untreated. Classic clue: An elderly patient who complains of night “glare” and decreasing vision, with a well-defined biconvex calcified disc posterior to the cornea on computed tomography (CT). It may also be a patient of any age who has received trauma…

Imaging General imaging features Imaging studies show thinning of the sclera with focal bulge. May be unilateral or bilateral. Computed tomography features Computed tomography (CT) shows bulging of posterior aspect of the globe away from optic disc, usually on the temporal aspect. Scleral thinning is associated with focal bulge. May see associated retinal or choroidal detachment, with or without hemorrhage. Magnetic resonance imaging features Magnetic resonance…

Imaging Magnetic resonance imaging (MRI) has the unique ability to characterize hemorrhage using hemoglobin’s paramagnetic qualities and makes it ideally suited to evaluate VLM. MRI clearly demonstrates the internal structure of subacute and chronic hemorrhagic cysts based on paramagnetic qualities. MRI may detect “flow voids” from large feeding vessels not appreciated by computed tomography (CT). Computed tomography features A soft, bulky, nonencapsulated infiltrative tumor of mixed…

Key points Definition: Orbital venous varix (OVV) is a rare intraorbital vascular malformation composed of single or multiple venous channels that may enlarge intermittently with changes in venous pressure. Synonym: Orbital venous malformation. Classic clue: Patients present with enophthalmos or acute intraorbital hemorrhage and are found to have a mass causing painful proptosis aggravated by head down position, coughing, sneezing, or Valsalva maneuver. OVVs may be…

Key points Definition: Cavernous sinus thrombosis (CST) is a potentially life-threatening complication usually secondary to infection, commonly coming from nose, sinuses, ears, or teeth. Synonyms: Cavernous sinus thrombophlebitis, septic cavernous sinus thrombosis. Classic clue: Patient presents with recent-onset HA, photophobia, periorbital edema, proptosis, ophthalmoplegia, and vision loss demonstrating dilated superior ophthalmic vein (SOV) and cavernous sinus (CS) thrombi. As with other rare entities, misdiagnosis is common.…

Key points Definition: Carotid-cavernous fistula (CCF) is an abnormal connection between the carotid artery and/or its branches and the cavernous sinus (CS). Classic clue: Patient presents with an acute onset of Dandy’s triad with pulsatile proptosis, chemosis, and bruit accompanied by pain and progressive visual loss. Initial computed tomography (CT) or magnetic resonance imaging (MRI) shows enlarged CS and superior ophthalmic vein (SOV) followed by CT…

Key points Definition: Congenital anophthalmia (CA) is a rare malformation causing unilateral, or bilateral eye absence. Classic clue: Anophthalmia is discovered at delivery and frequently found by fetal ultrasound (US). Anophthalmia is the medical term for absence of eyes coming from the Greek meaning “without eye.” CA arises as a consequence of damage to developing eye(s) during first 8 weeks of fetal development. , Imaging Computed…

Key points Definition: Congenital orbital teratomas (COTs) are rare tumors. They are usually benign, complex masses with cystic and solid components containing a mixture of fat, calcium, and bone. Synonyms: Orbital teratomas, teratomas. Classic clue: Huge orbital mass containing cystic and solid components, displacing and deforming the globe in young children with a complex, bizarre imaging appearance suggesting multiple tissue types. COTs are characteristically massive, causing…

Key points Definition: Pathologic entity caused by abnormal hypertrophy of the ocular hyaloid system. Classic clue: Child presenting at or soon after birth with leukocoria, micropthalmia, fluid-fluid level, no calcifications, and persistent Cloquet’s canal is virtually pathognomonic. In normal embryologic development, the primary vitreous is replaced by the adult secondary vitreous and does not normally hypertrophy or persist to infancy or childhood. Persistent hyperplastic primary vitreous…

Key points Definition: A coloboma is caused by a rare congenital defect with failure of the embryonic intraocular fissure to fuse during the first trimester of fetal development resulting in an elongated or malformed globe. Colobomas may arise in any part of the globe along the course of the uveal tract and may include iris, ciliary body, choroid, and optic nerve. Synonyms: Optic disc coloboma, coloboma…