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Case #3
History: Orbital Mass
Exam: fixed; does not move with the skin
Findings
Extraconal mass located at superolateral aspect of the anterior left orbit
At the left frontozygomatic suture
T1:
Heterogeneous signal with curvilinear rim of hyperintensity along the anterior aspect of the lesion.
T2:
Hyperintense
STIR:
Hypointense
Curvilinear focus of hyperintensity on T1 is hypointense.
DDx
Superolateral Orbital Mass:
Lacrimal gland neoplasm
Adenoid cystic carcinoma
Mucoepidermoid
Frontal sinus mucocele
Dermoid
Lymphoma
Orbital pseudotumor
Sebaceous cyst
Diagnosis
Superolateral Orbital Mass:
Lacrimal gland neoplasm
Adenoid cystic carcinoma
Mucoepidermoid
Frontal sinus mucocele
Dermoid
Lymphoma
Orbital pseudotumor
Sebaceous cyst
Orbital Dermoid
CT
(separate patient)
Mass located at the frontolacrimal suture
Markedly low attenuation
Density equal to fat
Fat density is pathognomonic.
Orbital Dermoid
Epidemiology
5% of orbital masses
Present form birth
Most present in childhood, teenage years
May present or grow at any age
Orbital Dermoid
Prognosis
Benign
Cosmetic issues
Treatment
Surgical resection is curative.
Must remove entire cyst, including growth center at periosteal surface.
If rupture: steroids, NSAIDs
Orbital Dermoid
Pathology
Choristoma (normal tissue in abnormal site)
Dermoid: Epithelial elements and dermal substructure (sebaceous glands, hair follicles, blood vessels, fat, collagen)
Epidermoid: Epithelial elements only
Capsule lined by keratinizing stratified epithelium
Orbital Dermoid
Imaging
Dermoid: More heterogeneous and contain fat
Epidermoid: More homogenous with density similar to fluid
Location
Tethered to periosteum near suture lines
Frontozygomatic suture (65-75%)
Frontolacrimal suture (2nd most common)
CT: Osseous remodeling (85%)
Orbital Dermoid
Clinical
Painless subcutaneous mass (85-90%)
May rupture (10-15%)
Traumatic or spontaneous
Inflammation can mimic cellulitis or rhabdomyosarcoma
