Orbital pathology Flashcards
How is the orbit divided?
Extraconal
Conal (muscles)
Intraconal
Cavernous malformation - Most frequent space
Lateral aspect of the intraconal space
Cavernous malformation - Morphology
Well-circumscribed, homogeneous and ovoid
Cavernous malformation - Epidemiology
Middle-age adults (43-48 years old)
Female predominance
Cavernous malformation - Signal intensity
T1: isointense to muscle
T2: hyperintense uniformly
Cavernous malformation - Enhancement pattern
Progressive and slow (complete feeling in 30 minutes)
Fibrous solitary tumor/Hemangiopericytoma - Most frequent space
Extraconal
Fibrous solitary tumor/Hemangiopericytoma - Morphology
Lobulated and well-circumscribed
Fibrous solitary tumor/Hemangiopericytoma - Signal intensity
T1: isointense
T2: hypointense with flow voids
Fibrous solitary tumor/Hemangiopericytoma - Enhancement pattern
Vivid and heterogeneous
Fibrous solitary tumor/Hemangiopericytoma - Cell origin
Spindle-cell neoplasm that originates from mesenchymal fibroblast-like cells (pericytes)
What’s the most common primary lesion of orbit in older adults? What tumor is the most common?
Lymphoproliferative lesion
Lymphoma
The majority of lymphoproliferative lesions are unilateral and extraconal (T/F)
True (76%)
Main characteristc of lymphoproliferative disease
Mold the orbital structures: globe, optic nerve, orbital wall
What happens to the bone surrouding the lesion?
Remodelling
Vary rarely it destroy bone
Half of lacrimal gland lesions are malignant and half are benign (T/F)
True
How are the lesions of the lacrimal gland divided?
Epithelial and non-epithelial
Lacrimal gland - Epithelial lesions
Pleomorphic adenoma
Adenoid cystic carcinoma
Lacrimal gland - Nonepithelial lesions
Lymphoproliferative
Pleomorphic Adenoma - Epidemiology
Most common benign neoplasm of the lacrimal gland
Slow-growing that manifest in the 4th or 5th decade
Pleomorphic Adenoma - Macroscopy
Well-circumscribed
Homogeneously enhacing mass
Bigger lesions may be heterogeneous secondary to cystic degeneration, hemorrhage, serous ou mucous collections or necrosis
Pleomorphic Adenoma - Signal
T1: hypointense
T2: hyperintense
Adenoid Cystic Carcinoma - Epidemiology
Most common malignancy of the lacrimal gland
Second most common epithelial lesion
4th decade of life
Adenoid Cystic Carcinoma - Pattern
Infiltrative
Propensity for perineural spread
Adenoid Cystic Carcinoma - Imaging
Irregular borders
Distortion of orbital contents
Bone erosions and calcification
Adenoid Cystic Carcinoma - What nerve is commonly affected?
Lacrimal branch of the ophthalmic nerve
Optic Nerve Glioma - Epidemiology
Most common primary tumor of the optic nerve
Children less then 8 years of age
NF-1
Optic Nerve Glioma - What’s the most common grade?
Grade I (Pilocytic astrocytoma)
Optic Nerve Glioma - Image Pattern
T2 hyperintense lesion with cystic spaces and variable enhancement
Optic Nerve Glioma - Apparence of the nerve in NF1 x Non-NF1
Tortuous, kinked and diffusely enlarged x fusiform dilatation
Optic Nerve Sheath Meningioma - Epidemiology
2% of all orbital masses
More common in women
5th decade of life
Optic Nerve Sheath Meningioma - Image pattern
Tram-track with bone remodeling and calcification (20-50%)
Schwannoma - Nerves
Mostly trigeminal nerve
May ocur in oculomotor, trochlear and abducens nerve, parasympathetic and sympathetic fibers, and ciliary ganglia
Schwannoma - Pattern
Extraconal and at the superior orbit (ophtalmic nerve)
Cone shaped or dumbbell
Schwannoma - Signal
T2 hyperintense, heterogeneous (cystic components)
Plexiform neurofibroma - Image Pattern
Serpentine soft-tissue mass extraconal with heterogeneous contrast enhancement and fluid-fluid levels
T2 hyperintense with a focal inner hypointensity
Metastasis - Common sites
Breast (50%)
Prostate
Melanoma
Lung
