1. Case study head and neck
Gerrit Engelbrecht
Department radiology
UFS

2. Case 24 year old male Refered from ophtalmology MRI and CT
Fluctuating mass, painless, left temporal region.( aware of it for several months, insidious in onset )
Mild proptosis of the left eye.
No visual field fallout.
No cranial nerve fallout.
Normal movement of the globe.
Neurological exam normal.
No systemic illnesses.
No histology available
MRI and CT

3. T2* FGRE

4. T2 Ax

5. T2 Flair

6. Sag T1

7. AxT1-fs SE S 3mm

8. Cor T1-fs SE S 4 mm

9. AxT2 FSE H 3 mm

10. Ax T1 SE + C

11. Cor T1 +C FS SE 4 mm

12. Ax T1+ C FS SE S 3 mm

13. Scout of CT

14. CT pre and post contrast

31. General features Best diagnostic clue: Location
Cystic, well-demarcated, anterior extraconal mass with fatty, fluid or mixed contents
Location
Tethered to orbital periosteum, near suture lines
Majority extraconal in superolateral aspect of anterior orbit, at frontozygomatic suture (65-75%)
Remainder mostly in superonasal aspect, at frontolacrimal suture, but can occur anywhere

33. Size Morphology Typically less than 1-2 cm in superficial lesions
Larger in deep, complicated lesions
Morphology
Ovoid, well-demarcated cystic mass
Most show thin definable wall (75%)
No nodular soft tissue outside cyst (80%)

34. Contents
Internal fat or fluid features; may be mixed or contain debris
Lipid components evident in 40-50% of lesions
Fluid-fluid levels in 5 % of lesions
Dermoid cysts typically but not exclusively contain fat and appear more heterogeneous
Epidermoid cysts typically have features similar to fluid and appear more homogeneous

35. Subtypes Superficial (simple, exophytic)
Typically smaller, discrete, rounded
Present in early childhood
Deep (complicated, enclophytic)
More insidious, frequent bony changes
May extend into sinuses, high deep masticator space, or intracranially

36. Radiographic findings
Scalloped bony lucency with sclerotic margins

37. CT Findings NECT CECT Hypodense fat in about half Calcification in 15%
Density -30 to -80 HU
Calcification in 15%
Fine or punctate, in cyst wall
osseous remodeling in majority of lesions (85%)
Pressure excavation; smooth, scalloped margins
Thinning of bone, may cause focal dehiscence
Bony tunnel, cleft, or pit in up to one-third, leading to “dumbbell appearance
Irregular margins indicate rupture and inflammatory reaction
Bony changes less common in superficial lesions
CECT
Mild, thin, rim-enhancement
Irregular inflammatory enhancement if ruptured

38. MR Findings T1WI T2WI TI C+ Diffusion and FLAIR
Strongly hyperintense (cf vitreous) if fatty contents
Isointense or slightly hyperintense otherwise
T2WI
Isointense or mildly hypointense (cf vitreous)
Heterogeneous debris
TI C+
Thin rim-enhancement
More extensive inflammation if ruptured
Diffusion and FLAIR
Epidermoid cysts show high signal as in other areas of CNS imaging

39. Ultrasonographic findings
Adequate for evaluation of simple superficial lesions without posterior extension
High internal reflectivity, variable attenuation
Debris may impair determination of cystic nature

40. Pathology (general features)
Developmental mass, non-neoplastic contents
Epidermoid: Desquamated keratinaceous debris, cholesterol; thin capsule
Dermoid: Keratin, sebaceous secretions, lipid metabolites, hair; fibrous capsule

41. Etiology
Congenital inclusion of dermal elements at site of embryonic suture closure
Sequestration of trapped surface ectoderm

42. Epidemiology Present from birth; spontaneous occurrence
10% of head and neck dermoid and epidermoid cysts are periorbital
5% of orbital masses

43. Gross pathological features
Whitish, well-delineated mass
Connected to orbital periosteum by fibrovascular tissue
Oily or cheesy material that is tan, yellow, or white
May contain blood or chronic blood products

44. Microscopic features Dermoid Epidermoid
Contains dermal structures, including sebaceous glands and hair follicles, blood vessels, fat and collagen within a fibrous capsule
Sweat glands in minority (20%)
Lined by keratinizing squamous epithelium
Epidermoid
Inner surface of thin capsule lined by keratinizing, stratified epithelium
Half show disruption of lining indicating rupture at some point
Inflammatory changes in 40%
Granulomatous reaction, particularly in deep, complicated lesions

45. Presentation Most common signs/symptoms:
Subcutaneous nodule near orbital rim
Smaller, little globe displacement
Painless subcutaneous mass (85-90%)
Clinical profile
Adult presentation
Nontender, firm; painless in 90%
Fixed to underlying bone (cf sebaccous cyst)
More commonly arises deep to orbital rim
Often near the lacrimal gland in the extraconal orbit
May present with rupture (10-15%)
Secondary to trauma or spontaneously
Less easily palpated; larger, globe displacement
Acute inflammation mimics cellulitis or inflammatory rhabdomyosarcorna
Less well-defined borders, more likely to erode into adjacent structures
Can result in entrapment, neuropathy
Mass effect if very large
Acquired epidermoid cysts of skin are common, but not included in this discussion
Diplopia due to restricted movement
Compromise globe or cranial nerves
. Childhood presentation
More common than adult

46. Demographics Age Gender: Equal or slight male predominance
Most frequently presents in childhood and teenage
Mean age in late teens to twenties
Simple, superficial lesions often present in infancy
May present or grow at any age
Occasionally will appear in adult and grow significantly over several months
Gender: Equal or slight male predominance

47. Natural history and prognosis
Benign lesion, usually cosmetic considerations
Very slow growth, usually dormant for years
Present during childhood but small and dormant
Becomes symptomatic during rapid growth phase ¡n young adult
Sudden growth or change following rupture
Significant inflammation and increased size
Rarely fistula may occur

48. Treatment Surgical resection is curative
Entire cyst must be removed to prevent recurrence, including growth center at periosteal interface
Approach depends on location in orbit
Lesions evident in early childhood should be removed to avoid traumatic rupture
Steroids or non-steroidal drugs to calm inflammation in ruptured lesions

49. References Grainger&Allison’s Diagnostic Radiology, Fifth Edition.
Head and neck Imaging, Fourth Edition, Peter M.Som & Hugh D Curtin.
Diagnostic imaging, Head and Neck, H. Ric Harnsberger

50. Differential diagnosis
Frontal mucocele
Benign (hyperplasia) or malignant (NHL)
Associated with chronic inflammatory sinus disease, e.g., polyposis and noninvasive fungal sinusitis
Other systemic malignancy
Langerhans histiocytosis, leukemia, neuroblastoma
Rhabdomyosarcoma
Expansile mass arising within frontal sinus
Malignancy of children and young adults
Idiopathic orbital pseudotumor
Invasive mass arising anywhere in orbit
Acute onset pain, edema, and proptosis
Vascular lesions
Infiltrating mass involving any area of orbit
Venolymphatic malformation
Lacrimal gland neoplasm
Capillary hemangiotna (infants)
Minor salivary: Adenoid cystic, mucoepidermoid
Sebaceous cyst
Ovoid; fat density and signal
Destructive bony changes in malignant lesions
Mobile, attached to the skin
Lymphoproliferative lesion
Predilection for lacrimal gland, can involve any area