Case study head and neck

1. Case study head and neck GerritEngelbrecht Department radiology UFS

2. Case • 24 year old male • Refered from ophtalmology • 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: • 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 • 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 • Hypodensefat in about half • 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 • Strongly hyperintense (cf vitreous) if fatty contents • Isointenseor slightly hyperintense otherwise • T2WI • Isointenseor mildly hypointense (cf vitreous) • Heterogeneous debris • TI C+ • Thin rim-enhancement • More extensive inflammation if ruptured • Diffusion and FLAIR • Epidermoidcysts 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 • 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: Painless subcutaneous mass (85-90%) • Clinical profile • Nontender, firm; painless in 90% • Fixed to underlying bone (cfsebaccous cyst) • May present with rupture (10-15%) • Secondary to trauma or spontaneously • Acute inflammation mimics cellulitis or inflammatory rhabdomyosarcorna • Can result in entrapment, neuropathy • Mass effect if very large • Diplopia due to restricted movement • Compromise globe or cranial nerves • . Childhood presentation • More common than adult • Subcutaneous nodule near orbital rim • Smaller, little globe displacement • Adult presentation • More commonly arises deep to orbital rim • Often near the lacrimal gland in the extraconal orbit • Less easily palpated; larger, globe displacement • Less well-defined borders, more likely to erode into adjacent structures • Acquired epidermoid cysts of skin are common, but not included in this discussion

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