Deepak M. Sampathu MD, PhD Assistant Professor of Clinical Radiology University of Pennsylvania

Transcription

1 Deepak M. Sampathu MD, PhD Assistant Professor of Clinical Radiology University of Pennsylvania

2 Objectives Recognize benign masses and masslike lesions of the neck and skull base Understand the imaging characteristics of benign masses and mass-like lesions of the neck and skull base on CT and MRI

3 Neck Masses By location: Midline/paramidline anterior neck Floor of mouth Submandibular space at angle of jaw Along lateral cervical nodal chain Posterior neck

4 Midline/paramidline anterior neck Thyroglossal duct cyst Laryngocele Dermoid/epidermoid cyst Venolymphatic malformation

5 Thyroglossal duct cyst Most common congenital neck mass Child / young adult Location Suprahyoid 20% At level of hyoid or infrahyoid 80% Painless fluctuant mass Risk of thyroid carcinoma Sistrunk procedure (Harnsberger, Handbook of Head and Neck Imaging, 1995)

6 Thyroglossal duct cyst

7 Thyroglossal duct cyst

8 Papillary carcinoma in TGDC

9 Epidermoid

10 Laryngocele Adulthood Enlarged laryngeal saccule Laryngeal saccule blind pouch arising from laryngeal ventricle Types: Internal External Mixed Laryngoscopy is critical (Harnsberger, Handbook of Head and Neck Imaging, 1995)

11 Laryngocele

12 Laryngocele

13 Floor of Mouth Ranula/Sialocele Abscess, Ludwig s angina Dermoid/ Epidermoid cyst Lymphatic malformation

14 Floor of Mouth Lesions (Vogl et al, AJR 1993)

15 Ranula Peak prevalance age years Pseudocyst in floor of mouth Submandibular duct obstruction Types Simple Plunging/Diving DDx: Sialocele - Ruptured SMD extravasates saliva into sublingual space

16 Simple ranula

17 Plunging Ranula

18 Plunging Ranula

19 Floor of Mouth Infection Clinical findings get history! Imaging findings dirty fat Thickening of platysma/skin Abscess: peripherally-enhancing collection Most common etiology: odontogenic Ludwig s angina: 5% fatality rate Mixed bacterial infection: aerobes/anaerobes Potential airway compromise

20 Infection - Ludwig angina

21 Dermoid

22 Dermoid/Epidermoid cyst Usually present at age Terminology Epidermoid: squamous epithelial lining Dermoid: squamous epithelial lining + skin appendages (sebaceous glands, hair follicles) [Teratoma: true neoplasm with tissue of one or more germ layers] Etiology: Trapped pouches of ectoderm or failure of ectoderm to separate from neural tube Dermoid: 5% malignant degeneration to SCCa

23 Dermoid/Epidermoid cyst Imaging characteristics Epidermoid CT: fluid attenuation MRI: hyper on T2, hypo on T1 Restricted diffusion Dermoid More variable on CT/MR Restricted diffusion

24 Dermoid/epidermoid

25 Presumed epidermoid

26 Lymphatic malformation lymphangioma, cystic hygroma ~50% present at birth or before age 5, do not spontaneously regress Slow-flow vascular malformation containing embryonic lymphatic sacs Can occur in any H&N space transspatial mass with fluid-fluid levels Venolymphatic malformation: venous and lymphatic elements in same mass

27 Lymphatic malformation

28 Lymphatic malformation

29 Submandibular space at angle of jaw 2 nd Branchial cleft cyst (DDx - Cystic/necrotic level IIA lymphadenopathy ) Plunging ranula/sialocele Abscess/Ludwig s angina Lymphatic malformation

30 Cystic/necrotic lymphadenopathy Infectious etiologies Mycobacterial Bacterial Neoplastic etiologies Squamous cell carcinoma Papillary thyroid carcinoma (lymphoma rarely cystic-appearing)

31 2 nd branchial cleft cyst Most common branchial apparatus anomaly Typically present at age subtypes based on location Classic is type 2: Posterior to submandibular gland Anteromedial to sternocleidomastoid muscle Lateral to carotid sheath

32 Branchial Apparatus (Ibrahim et al. Neurimag Clin N Amer 2012)

33 2 nd branchial cleft cyst

34 2 nd branchial cleft cyst

35 Lymphadenopathy R tonsillar SCCa

36 Metastatic lymphadenopathy from oropharyngeal SCCa

37 2 nd branchial cleft cyst

38 Cystic lesion at level 2A in adult Consider cancer until proven otherwise Increasing incidence of HPV-related squamous cell cancer in adults < age 40 Male>female, nonsmokers Occur in oropharynx Propensity for cystic adenopathy Primary tumor may be small FNA for workup (avoid open biopsy) If FNA inconclusive, some advocate for blind oropharyngeal biopsies/pet in workup

39 Along cervical nodal chain Suppurative or cystic/necrotic lymphadenopathy 2 nd /3 rd Branchial cleft cyst Paraganglioma Schwannoma

40 Suppurative Lymphadenitis

41 Carotid body paraganglioma Benign neuroendocrine neoplasm arising in paraganglionic tissue Slowly growing, painless, pulsatile mass Vascular mass splaying ICA and ECA salt and pepper appearance in larger tumors on T1WI: Salt = areas of high signal intensity Pepper = flow voids Intense rapid enhancement

42 Paragangliomas

43 Carotid body paraganglioma

44 Multiple paragangliomas Multiple gene mutations identified in familial and sporadic types SDH: succinate dehydrogenase gene RET protoongogene: multiple endocrine neoplasia (MEN) syndromes VHL gene: von Hippel-Lindau syndrome

45 Carotid space schwannoma Benign tumor of Schwann cells that wrap around a nerve Clinical presentation: Typical: asymptomatic palpable mass if large, may cause dysphagia or occlusion of IJV Horner syndrome Hoarseness (vocal cord paralysis Imaging: lack of flow voids Dense uniform enhancement +/- intratumoral cysts

46 Schwannoma

47 Parotid space 1 st Branchial cleft cyst Parotid lymphoepithelial cyst/sialocele/sialectasis Lymphoepithelial lesions (bilateral and multiple, HIV or Sjogren) Warthin s tumor (bilateral parotid tails)

48 1 st branchial cleft cyst 1 st branchial arch extends from EAC, through parotid gland, to submandibular space Locations Adjacent to external auditory canal Intraparotid/periparotid CT/MR cannot differentiate from cystic parotid mass

49 1 st Branchial Cleft Cyst

50 Infected 1 st BCC

51 Benign Lymphoepithelial lesions in HIV Intraparotid May be: Cystic Mixed cystic/solid Solid (lymphadenopathy) DDx: Sjogren s Warthin s tumors

52 Lymphoepithelial Lesions

53 Posterior cervical space Cystic hygroma (very large lymphatic malformation presents at < 2-year-old) Lymphatic malformation (smaller lymphatic malformation presents at any age) Level 5 Cystic/necrotic lymphadenopathy 3 rd Branchial cleft cyst (posterior to the carotid, rare)

54 Lymphatic malformation

55 Lymphatic malformation

56 Infectious lymphadenopathy - bacterial

57 Skull Base Benign masses Anterior skull base Central skull base Posterior skull base (jugular foramen)

58 Anterior Skull Base Fibrous Dysplasia Cephalocele Meningioma

59 Fibrous Dysplasia Benign fibro-osseous lesion in which normal bone is replaced by weak osseous & fibrous tissue Classic appearance groundglass density on CT Variable enhancment of fibrous component

60 Fibrous Dysplasia

61 Fibrous Dysplasia

62 Cephalocele Cephalocele: general term for protrusion of intracranial contents through defect in calvarium or skull base Meningoencephalocele/encephalocele: Brain tissue, meninges, and CSF Meningocele: Meninges and CSF only CT: delineation of osseous defect MR: heterogeneous appearance reflecting brain tissue and CSF contents

63 Ethmoid meningoencephalocele

64 Meningioma Most common extra-axial intracranial neoplasm Typical meningioma WHO grade 1 (~70%) Atypical meningioma WHO grade 2 (~30%) Malignant meningioma WHO grade 3 (~1%) Well-circumscribed extra-axial mass with dural attachment Majority enhance homogeneously and intensely Necrosis, cysts, hemorrhage (8-23%) Calcifications (20-25%)

65 Meningioma

66 Central Skull Base Meningioma Pituitary Macroadenoma Chordoma Benign Fibrofatty lesion (arrested pneumatization) Cholesterol granuloma

67 Meningioma

68 Meningioma

69 Pituitary Macroadenoma Sellar mass without separate identifiable pituitary gland Most common suprasellar mass in adults superior extension of macroadenoma +/- mass effect on optic chiasm +/- cavernous sinus invasion Usually isointense with gray matter Most enhance heterogeneously

70 Pituitary Macroadenoma

71 Pituitary Macroadenoma

72 Chordoma Arises primitive notochord remnant Rare, locally aggressive Considered low-grade malignancy Local recurrence is common despite combined surgical and radiation therapy Imaging: destructive midline mass which is hyperintense on T2WI

73 Clival Chordoma

74 Clival chordoma

75 Cholesterol Granuloma Expansile lesion in petrous apex consisting of fibrosis and vascular proliferation Giant cell reaction to deposition of cholesterol crystals in air cells CT: sharply marginated, expansile lesion MR: high signal intensity on T1WI, no internal enhancement

76 Cholesterol Granuloma

77 Benign fibro-fatty lesion of sphenoid Synonym: arrested pneumatization of sphenoid Common incidental finding on imaging leave me alone lesion Nonexpansile lesion in sphenoid bone with sclerotic margins Internal fat attenuation is invariably present

78 Benign fibro-fatty lesion of sphenoid

79 Encephalocele in sphenoid siunus

80 Posterior Skull Base Lesions of jugular foramen: Paraganglioma Schwannoma Meningioma

81 Glomus jugulare paraganglioma Benign tumor arising from neural crest cells in/around jugular foramen CT: permeative bone destruction around jugular foramen MR: vascular mass

82 Glomus jugulare paraganglioma In-111 Octreoscan

83 Glomus jugulare paraganglioma

84 Jugular foramen schwannoma Benign neoplasm of differentiated Schwann cells around cranial nerve 9, 10, or 11 in jugular foramen CT: well marginated, expanded jugular foramen without permeative destruction MR: tubular or dumbell-shaped mass; no flow-voids Homogeneously enhancing except for cystic areas in larger lesions

85 Jugular foramen schwannoma

86 Jugular foramen schwannoma

87 Jugular foramen meningioma Mass arising from arachnoid meningothelial cap cells along cranial nerves 9-11 in jugular foramen CT: permeative/sclerotic margins MR: enhancing mass with dural tail(s), no flow voids

88 Jugular foramen menngioma

89 Objectives Recognize benign masses and masslike lesions of the neck and skull base Understand the imaging characteristics of benign masses and mass-like lesions of the neck and skull base on CT and MRI

90 Thanks