Key points Definition: Rhabdomyosarcoma (RMS) is a relatively rare sarcoma, frequently found in children aged between 1 and 5 years. Classic clue: A 5-year-old old child is referred by a pediatrician with a history of possible recent trauma, developing rapid onset unilateral proptosis, globe displacement, and showing a mass isodense and isointense to muscle on computed tomography (CT) and T1 magnetic resonance imaging (MRI), hyperintense on…

Key points Definition: Esthesioneuroblastoma (ENB) is a rare neuroendocrine malignancy of neural crest origin arising from olfactory epithelium near the cribriform plate and the nearby nasal cavity. ENB may invade the orbit, causing ophthalmic signs and symptoms. Synonym: Olfactory neuroblastoma. Classic clue: The patient presents with many months of nonspecific symptoms, including stuffy nose, epistaxis, rhinorrhea, anosmia, headache, facial pain, diplopia, or proptosis. , Classically found…

Key points Definition: Isolated metastasis to the optic nerve is rare and is often overlooked or misdiagnosed initially. Classic clue: Typically, a middle-aged female presents with “a little blurred vision,” further inquiry identifies pain, proptosis, reduced visual acuity, and bitemporal hemianopsia with enhancing abnormality related to the optic nerve (ON) sheath(s). Her past medical history reveals that she first had breast carcinoma 10 years ago with…

Key points Definition: Leukemia presenting as an orbital mass portends a more serious prognosis as these patients continue to show significantly lower survival rates than other leukemia patients. Synonym: A subset of orbital leukemia includes: granulocytic sarcoma, chloroma, or myeloid sarcoma. Classic clue: An 8-year-old presenting with a sensation of fullness, double vision, and proptosis has a homogeneous extraconal mass that molds to orbital wall without…

Key points Definition: Retinoblastoma (RB) is a rapidly developing intraocular cancer arising from immature retinal cells. Classic clue: A calcified posterior globe mass in an infant or young child is an RB until proved otherwise. RB is the most common intraocular tumor in children; 95% of cases are in children under 5 years. , The most common and obvious sign of RB is leukocoria, also known…

Key points Definition : Ocular melanoma is the most common intraocular malignancy in adults. Synonyms : Orbital melanoma, uveal melanoma, choroidal melanoma. Classic clue: A “collar button” enhancing intraocular mass in adults. Computed tomography (CT) shows: Ocular melanoma is hyperdense. Ocular melanoma has moderate contrast enhancement. Magnetic resonance imaging (MRI) shows: T1 bright (most). T2 dark. T1 + Gd moderate enhancement. Imaging computed tomography Features Precontrast…

Key points Definition: Ocular adnexal lymphoma (OAL) is one of the most common orbital tumors in adults, accounting for 50% of orbital malignancies. Synonym: Orbital lymphoma (OL). Classic clue: An older patient presenting with an orbital mass causing progressive exophthalmos, ptosis, diplopia and restricted ocular movement. Imaging shows restricted diffusion with the “apparent diffusion coefficient (ADC) black hole sign.” Imaging Computed tomography features Neurological examination computed…

Key points Definition: Usually found in middle-aged adults, orbital schwannomas (OS) are well-defined, encapsulated, slowly growing benign tumors arising from peripheral nerve Schwann cells, and comprise 1% to 2% of orbital tumors. Classic clue: Middle-aged patient presenting with optic neuropathy, proptosis, or diplopia with a well- circumscribed retrobulbar intraorbital mass separate from the optic nerve (ON) which on dynamic magnetic resonance imaging (MRI) shows enhancement progressing…

Key points Definition: Orbital lipomas (OL) are very rare tumors that are usually benign, accounting for less than 1% of orbital tumors. Classic clue: The patient presents with a well-circumscribed homogeneous orbital mass with low attenuation approximating orbital fat, having no calcifications or fluid-fluid level suggestive of a dermoid or teratoma. True primary OLs are as uncommon as extraorbital lipomas are common. While usually having a…

Key points Definition: Dermoids originate from totipotential germ cells. Present at birth, these differentiate abnormally, developing characteristics of mature dermal cells. Synonym: Orbital dermoids, retrobulbar orbital dermoids, or deep dermoids. Classic clue: Well-circumscribed encapsulated mass with low Hounsfield numbers, filled with high T1 signal material. Displacement of globe and ocular muscles may impair ocular motility. Compression of the optic nerve (ON) may result in visual impairment.…

Key points Definition: Optic nerve meningioma (ONM) is a rare, benign tumor arising from arachnoid cap cells in meninges covering the optic nerve (ON). Synonym: Optic nerve sheath meningioma (ONSM). Classic Clue: Appears as an enhancing mass surrounding the nonenhancing ON with “tram track” calcifications and perioptic cysts. The second most common ON tumor. Calcification is a characteristic feature on computed tomography (CT). Main differential diagnosis…

Key points Definition: Optic nerve glioma (ONG) is a type of juvenile pilocytic astrocytoma (grade 1 astrocytoma) that occurs more commonly in children and young adults. Synonym: Optic pathway glioma (OPG). Classic clue: Sausage-shaped diffuse fusiform enlargement and “kinking” of the intraorbital optic nerve (ON). More favorable prognosis compared to other astrocytoma types. Most common primary neoplasm of the ON. Bilateral ONG is pathognomonic of neurofibromatosis…

Key points Definition: Orbital cavernous hemangioma is a benign, slow-growing, vascular lesion manifesting as painless, progressive proptosis. Synonyms: Ocular cavernous hemangioma, orbital cavernous malformation, orbital cavmal. Classic clue: Well-circumscribed, enhancing intraconal mass in adult patients. Usual imaging appearance Computed tomography (CT) features: Intraconal mass. Homogeneous, well-circumscribed. Enhancement ↑↑↑↑. Magnetic resonance imaging (MRI) features: T1 isointense. T2 hyperintense. T1 + Gd enhancement. “Blooming” artifact. Most common orbital…

Key points Definition: Retinal detachment (RD) is a condition in which the inner retinal layer peels away from the middle choroidal layer of the globe permitting fluid to accumulate in what was previously only a “potential space.” It is a true medical emergency, progressing to vision loss and permanent blindness if not repaired within 24 to 72 hours. Classic clue: Middle-aged or older patient presents with…

Key points Definition: An ocular prosthesis (OP) is a device that replaces the native eye after enucleation, evisceration, or exenteration. Also known as: glass eye, artificial eye. Classic clue: The patient usually visits the radiology department for neuro computed tomography (CT) or magnetic resonance imaging for a problem totally unrelated to the OP and the device is first found by an unsuspecting resident or fellow with…

Key points Definition: Phthisis bulbi (PB) is a generic descriptive term for the ocular globe’s “end-stage” appearance after wasting away, becoming anatomically disfigured, and shrunken as a result of a range of possible prior insults. Also known as: end-stage eye, blind hypotensive eye, ocular phthisis, atrophia bulbi, atrophy eyeball, shrunken eyeball, phthisis eyeball, eyeball atrophy, and others. Classic clue: Patient commonly presents with unilateral blindness related…

Key points Definition: Ruptured globe (RG) occurs when the integrity of the eye is breeched by blunt or penetrating trauma causing full-thickness corneal or scleral breech. This is an ophthalmologic emergency. Synonym: Shattered globe. Classic clue: A man in his 30s with eye pain after having been struck by a projectile while carrying out a home-improvement project is sent by the emergency department with a request…

Key points Definition: Ocular lens displacement (OLD) refers to the malposition of the lens relative to its normal location as a result of disruption of the zonular fibers, which normally connect the lens to the ciliary body. Synonyms: Lens luxation, lens subluxation, dislocation of lens, ectopia lentis . Classic clue: The patient presents posttrauma with visual disturbance, monocular diplopia, reduced visual acuity, reduced near vision, and…

Key points Definition: Anterior chamber perforation causes loss of aqueous humor resulting in flattening or obliteration of the space between the lens and cornea. Classic clue: The patient presents with potentially penetrating eye trauma, and is found to have a small anterior chamber compared with the contralateral eye. Imaging Computed tomography features Imaging may be requested to locate intraocular or intraorbital foreign bodies. The patient may…

Key points Definition: Blowout orbital floor fractures can be repaired using titanium mesh, which gives a characteristic recognizable imaging appearance on computed tomography (CT) and magnetic resonance imaging (MRI). Classic clue: The patient presents for CT or MRI for his or her current complaint, frequently trauma to the head or face. Neither the patient nor the referring physician mentions the fact that the patient has undergone…