1. The document discusses various head and neck masses and their imaging appearance on CT and MRI. 2. Key neck masses discussed include lymph nodes, tonsillar abscesses, benign mixed tumors, minor salivary gland malignancies, and squamous cell carcinoma of the nasopharynx and oropharynx. 3. Important imaging findings for differentiating benign from malignant lesions are described.

1. DR/ Wafik Ebrahim, MD
Assistant Professor of Rradiodiagnosis
Faculty of Medicine
Alazhar University

2. Imaging modalities:
 CT
 MRI
 US:
 Plain X ray and conventional studies.
 Isotope scan.
 Angiography.
Multiplanner capability allows good
anatomical description.
Vascularity of lesion.
Consistency of the lesion.

3. CT scan:
 IV contrast is important for better
cracterization of the mass.
 Start from superior orbital rim to apex of
the lung. Extension to carina may be
accomplished according to suspected
disease.
 To avoid artifacts of dental filling, planes
are parallel to skull base down to
alveolar ridge then parallel to body of
mandible.

4. MRI:
 Use dedicated surface colis better than
cervical coil for better resolution.
 T1 in the 3 planes followed by T2 in planes
best depict the lesion.
 4-6mm thickness with 1-2mm gap.
 IV contrast is not routine due to inherent
tissue characterization of MRI.
 If IV contrast is used, fat sat sequences
are added.

5. Neck triangles:

6. Lymph nodes:
 Enlarged lymph node is the most
common neck mass in adults.
 About 300 nodes are located in the head
and neck. They are divided in groups
described by the anatomist Rouviere.
20-40 years—lymphoma
>40 years----metastasis
6. Submental1. Occipital
7. Sublingual2. Mastoid
8. Retropharyngeal3. Parotid
9. Anterior cervical4. Facial
10. Lateral cervical.5. Submandibular
The first 6 form
lymphoid collar at
junction between
head and neck

7. Lymph nodes groups:

8. Lymph nodes:
 NORMAL nodes are oval with fatty
sinus.
 Size criteria for benign nodes:
 < 1.5cm for IJC near angle of mouth.
< 0.8cm for retropharyngeal nodes.
< 1cm for the rest of groups.
 Pathological signs:
Central necrosis (DD fatty hilum “peripheral
fat density”)
Matting.
Infiltrated surrounding fat planes.

9. Lymph nodes stations:
III: Between
hyoid bone and
inferior cricoid
margin
V: PCS: SAC:
A: skull base
to cricoid.
B: cricoid to
clavicle.
IV cricoid to
clavicle
VI: visceral s.
nodes (hyoid to
manubr)
VII: Super.
Mediast.

10. LN:
 Other groups include:
Parotid group:
Retropharyngeal group.
Facial group:

11. LN

12. PMS: Anatomy

13. Pharyngeal mucosal space
(PMS)
 Psudomass:
 Asymmetry of fossa of Rosenmuller (lateral
pharyngeal recesses) may result from
inflammatory debris or asymmetry in the
amount of lymphoid tissue thereby giving the
impression of a mass.
A mass is ruled out when:
1. The adjoining soft tissue planes in the PPS
and RPS are maintained.
2. The nasopharyngeal mucosa is clinically
intact.
3. The collapsed recess opens when
rescanning by CT scan is used during the
Valvalva maneuver.

14. Adenoid hypertrophy:
 It represents normal immunolgical
activity that starts at age of 2-3 years
and regresses during adolescence.
 Absence of adenoid tissue in young
children should alert for immune
disease.
 Smoking can produce adenoid
hypertrophy in adults.

15. Adenoid:
 Hypertrophied
adenoid should be
confined to mucosal
space with intact
underlying fascia.

16. Thornwaldt cyst:
CT: Hypodense lesion:
CECT: May be wall enhancement.
•MRI:
•TI: intermediate to high
according to protein contents.
•T2: High signal
•+C: may be wallenhancement.

17. Tonsillar abscess:
Cellulitis versus abscess: As a rule in cervical
infection: Thickening of overlying skin or mucosa,
smudging of the fat planes (or linear opacities),
thickening of adjacent muscles, and enhancement of
fascial planes WITHOUT fluid collection denote
cellulitis but if WITH fluid seen it means abscess.
LOOK CAREFULLY TO FAT PLANES BY
ADUSTING WINDOW AND LEVEL.

18. Tonsillar abscess:

19. Tonsillar abscess:
 DD:
Tonsillar retntion cyst.
Lymphoid hyperplasia.
Retropharyngeal abscess.
Benign mixed tumor of salivary gland.
Tonsillar SCCA.
NHL.

20. Retention cyst:

21. Retention cyst:

22. Benign mixed tumors of minor
salivary gland tumors (BMT):
NO invasion of
surrounding
structures

23. MST
 CT:
Isodense mass lesion.
Minimally enhancing.
Necrosis and calcifications may be seen.
Bone remodeling (benign longstanding
feature).

24. BMT
PEARL
SHAPED
NO PALATE
DESTRUCTION
RIGHT
MASTOIDITIS NO muscle
invasion
T1: isointense to muscle
T2: variable mostly hyper
If calcified, foci of low signal.
T1+C: intense enhancement

25. BMT:
 Age: 30-60 years. But may be any age
even in neonate.
 DD:
Thyroglossal duct cyst in foramen coecom.
Retention cyst.
SCCA.
Malignant salivary gland tumor (poorly
defined).

26. Minor salivary gland
malignancy:
 Rare aggressive tumor (1/10 of minor
salivary glandstumors.
 Occurs in adults.

27. Minor salivary gland
malignancy:
 Pathology: adenoid cystic carcinoma
and mucoepidermoid carcinoma.
 Rarely complicates pleomorphic
adenoma.
 Treatment is wide surgical excision.

28. Minor salivary gland
malignancy:

29. Minor salivary gland
malignancy:
 MRI:
T1 WI: Isoointense mass.
T2: Variable signal.
Low signal (more cellular poorer prognosis).
High signal (less cellular better prognosis).
T1+C enhancing with infiltrating margin.
Add fat sat sequence for better assessment of
perineural spread).

30. Minor salivary gland
malignancy:
T1+C
T2
PPS
RPS:LN

31. Minor salivary gland
malignancy:
Perineural
spread CN V3
through F. Ovale

32. Minor salivary gland
malignancy:
 DD:
Benign mixed salivary gland tumors (well
defined and regular non-invasive margin).
SCCA (usually with malignant adenopathy).
Lymphoma (usually with associated non-
necrotic nodes).

33. Squamous cell carcinoma
“SCCA” Nasopharynx
 SCCA arising from nasopharynx has
three histological subtypes:
1. Keratinizing SCCA (WHO type 1).
2. Non-Keratinizing SCCA (WHO type 2).
3. Undifferentiated SCCA (WHO type 3).
 Size: Usually multiple CMs when
discovered.

34. SCCA Nasopharynx:
Spread
Anterior: Nasal cavity
then ptrygopalatine
fossa
Anteroinferior to
levator velli paltini ms
with eustachian T.
dysfunction
Lateral to PPS
then to MS
(then foramen
ovale up)
Posterior to
RPS to PVS
and spineInferior to
oropharynx
Superior
to skull
base

35. SCCA Nasopharynx:
Spread
 Lymphatic spread: usually seen at
presentation: retropharyngeal nodes,
jagular nodes and spinal accsssory
nodes.
 Blood spread (10% at time of
presentation): to bone > lung > liver. )

36. SCCA: Imaging:
 CT scan: Isodense
poorly enhancing
mass
 look also at bone
window to assess skull
base.
 Show the mass and
extension.
 Look at skull base
foramina

37.  MRI: Low T1 signal and internediate to
high T2 signal with intense postcontrast
enhancement.
 Add fat sat. for
 Better depiction of bone marrow invasion.
 Better evaluation of perineural spread.

38. SCCA: Imaging:
 NSCCA starts usually in the fossa of
Rusenmuller and has same signal and density
to normal mucosa. First signs are:
 Asymmetry of nasopharyngeal mucosa (regarding
cautions said before), attention is applied to:
○ Fat stripe between levator and tensor velli palatine
muscles. Obliteration mass.
○ Middle ear collection warning sign.
○ Associated lymphadenopathy especially
retropharyngeal nodes.

39. SCCA: Imaging:
 Fat stripe between levator and tensor velli
palatine muscles. Obliteration mass.

41. Staging:

42. DD
 Benign mixed tumor (non invasive).
 Malignant salivary tumor (may be
indistinguishable). .
 NHL.

43. Squampos cell carcinoma
Oropharynx:
 Location:
 Lingual tonsils (posterior to circumvillate
papillae). The mass is more invasive with
difficult early detection because it has same
density and signal like the lymphoid tissue of
normal lingual tonsils.
 Palatine tonsils and facuial arches.

44. Lingual tonsil SCCA spread
pattern:
Anterior: root of tongue,
subliungal space
(neurovascular bundle)
and floor of mouth.
Posterolateral:
palatine tonsils and
tonsillar pillars.
Inferior to
supraglottic larynx
and preepiglottic
fossa.

45. Lingual tonsils SCCA:

46. MRI

47. Palatine tonsils SCCA:
 Tonsils > Anterior pillar } posterior pillar.
 Asymmetry of tonsils may be seen
normally however mass is suspected
when there is obliteration of fat planes in
PPS and / or associated lymph node
enlargement.
 Mass may spread to PPS, masticator
space (foramen ovale) or carotid space.

48. Palatine tonsils SCCA:

49. Palatine tonsils SCCA:

50. Non-Hodjkin lymphoma:

51. NHL

52. Non-Hodjkin lymphoma:
Benign mixed
salivary tumor
was
suspected

53. Parotid space:
 Anatomic considerations:

54. Parotid space:

55. Parotid space: Acute
parotitis Bacterial:
 Suppurative infection  abscess.
 Usually unilateral.
 Viral:
 75% bilateral though one is earlier involve.
 May be associated other sialadenitis.
 Calcular induced:
 Stone impacted in the duct.
 Unilateral

56. Acute parotitis: imaging:
 CT: Cuts taken parallel to mandible to avoid artifacts of
dental filling.
 Enlarged ill-defined hyper dense gland with
smudging of adjacent fat planes.
 Cystic changes denote abscess formation.
 search for a stone in the duct.
 MRI:
 Diffuse gland enlargement:
 Liquefaction means abscess.

57. Acute parotitis: imaging:

58. Acute parotitis: imaging:

59. Sjogren disease:
 Bilateral parotid enlargement with multiple
intraglandular cysts and occasional
calcifications.
 Diffuse disease is usual but sometimes
single localized disease: DD from tumor.
Age: 50-70 Y
Juvenile type < 20 Y
mostly cures at puberty.
Higher incidence in
females.

60. Sjogren disease:
 Stages:
 Early: the glands may look normal.
 Intermediate: Multiple small intraparotid
cysts.
 Late: gland destruction with variable sized
cysts.
 At any stage there may be solid masses
related to lymphocytes aggregations.
 Calcifications are common.

61. Sjogren disease:

62. Benign mixed tumors:
Parotid
 Small lesion: is sharply demarcated ovoid
intraparotid mass with homogeneous
enhancement.
 Large mass >2cm is lobulated
heterogeneously enhancing.
 Deep lobe mass is pear shaped pushing
PPS medially. .
Usually unilateral
mass.
Age> 40 years.

63. Benign mixed tumors:
Parotid
Facial nerve palsy is
rare.

64. Warthin Tumor:
 Sharply marginated mass mostly in
parotid tail.
 Parenchymal inhomogeneity is a rule
with cystic components. Cyst with solid
nodule is also seen.
 Multicentericity and bilaterality: 20%.

65. Warthin Tumor:
Inhomogeneity
is a rule
Cyst with solid
nodule

66. Malignant tumors:
 Mucoepidermoid carcinoma:
 Low grade: well circumscribed mass lesion.
 High grade: infiltrative heterogeneous mass.
 Adenoid cystic carcinoma:
 Low grade: well circumscribed mass lesion.
 High grade: infiltrative heterogeneous mass.
 Lymphoma: may be primary or secondary
with associated multiple bilateral lymph
nodes enlargement.

67. Mucoepidermoid
carcnoma
Adenoid cystic carcinoma

68. Carotid space:
SHN IHN

69. CS: Pathology:
 Arterial disease:
 Thrombosis, dissection aneurysm or
pseudoaneurysm.
 Venous disease:
 Thrombosis or thrombophlibitis.
 Benign tumors:
 Glomus jagulare and glomus vegale
paragangliomas.
 Carotid body paraganglioma.
 CN 9-11 Schowanoma and neurofibroma.
 Jugular foramen meningioma.
 Malignant tumors
 Spreading SCCA or lymphoma.

70. CS
Kissing ICAs Ectatic ,medially
migrating ICA (RPS)

71. IJV thrombosis

72. Paragangliomas (glomus
tumors):
 They are neoplasms of neural crest cell
origin that arise within the adventitial layer
of blood vessels at multiple sites in the
head and neck.
 They include the middle ear (glomus
tyrnpanicum, parapharyngeal space
(glomus jugulare) and larynx.
 The two most common paragangliomas to
present as a neck mass
 Carotid body tumor (carotid bifurcation)
 Glomus vagale (along the nodosa ganglion of
the vagus nerve).

73. Paragangliomas
 The constant features:
 CT: intense progressive enhancement.
 MRI: pepper (flow void blood vessels) and
salt (foci of hemorrhage) appearance on T1
WI.
 Mass in the neck showing signal void
blood vessel signal should alert for
paraganglioma (considering anatomical
location).

74. Paragangliomas:
 Carotid body tumor arise juxtahyoid and
splays the ICA and ECA.
Multiplicity is
common (10-30%)

75. Paragangliomas:
 Glomus vagale arises in the SHN and
displaces ICA anteromedially and IJV
posterolaterally.

76. Neurogenic tumors:
 Vagal Neurofibroma and Schwanomas:
without history of neurofibromatosis they
could not be differentiated.
 They have same location like glomus
vagale displacing the ICA anteromedially
and the IJV posteromedially.
 They show any pattern of enhancement
from non to avid enhancement.
 DD from paraganglioma by absence of
flow void and pattern of enhancement.

77. Vagal Schwanoma

78. Vagal neurofibroma

79. Masticator space:

80. Benign masticator space
hypertrophy:
 Smooth enlargement of the
muscles of mastication.
 May be up to 3 times volume
increase.
 May be bilateral with
asymmetry.

81. Motor denervation:
 Denervation of muscles supplied by
mandibular division of trigeminal nerve
(only motor branch).
 The involved muscles are:
 Muscles of mastication:
○ Masseter, Ptrygoid, Temporalis muscles.
 Others supplied by V3 nerve:
○ Mylohyoid and anterior belly of digastric
muscle.
○ Tensor veli palatini and tensor tympani.

82. Motor denervation: stages
 Acute stage: (<1 month):
 Muscle enlargement with edema and
enhancement.
 Subacute stage: (<12- 20 months);
 Fatty replacement with starting atrophy.
 Enhancement may be noted.
 Chronic: (>12-20 months):
 Fatty replacement with volume loss.

84. Motor denervation

85. Motor denervation

86. Masticator space infection:
 Mostly secondary to molar tooth
infection.
 Same like all infections in head and
neck:
 Cellulitis
 Abscess formation.

87. Masticator space infection:

88. Mandibular nerve schwanoma:
 May involve the mandibular nerve through
its course from Meckel’s cave and
downward.
 May involve mandibular nerve branch
including inferior alveolar and mental
nerves.
 It widens the foramen if it is site of
involvement.

89. Schwanoma: Imaging
 CT:
 Isodense ovoid smooth mass lesion with
occasional cystic changes.
 Mild to moderate homogeneous or heterogeneous
enhancement (due to cystic changes).
 Muscle denervation changes may be noted.

90. Scwanoma: CT

91. Schwanoma:
 MRI:
 T1: isointense mass. Hypointense cystic
areas may be seen. Nemorrhagic bright foci
may be also noted.
 T2: Iso to hyperintense. Cystic changes may
be also senen.
 T1+C: variable enhancement.

92. MRI

93. Chondrosarcoma:
 Malignant tumor of cartilage.
 Soft tissue mass in masticator space close to
mandible with bone erosion and variable
calcification pattern.
 CT:
 Soft tissue density with calcification:
○ Low grade  crescents and rings.
○ High grade  amorphous or no calcifications.
 Heterogeneous peripheral enhancement.

94. CT

95. MRI
 T1:
 Homogeneous intermediate signal. Cartilage
matrix or calcifications make it
heterogeneous.
 Bone marrow infiltration (best seen on T1).
 T2:
 High signal is characteristic.
 Calcifications make it heterogeneous.
 T1+C: enhancement increases with
grade.

96. MRI

97. Mandibular nerve perineural
infiltration:
 Can occur at any point from mental
foramen to root entery zone of CN V on
lateral pons.

98. Perineural spread:
 CT:
 Widened neural foramen of nerve bony canal.
 Nerve thickening and enhancement.
 MRI:
 Nerve thickening with low T1 signal, high T2
signal and intense postcontrast enhancement.
 Infiltration of masticator space with involvement
of the fat planes especially the perineural fat.
 Infiltration of fat planes below foramen ovale.
 Evidence of denervation of the muscles in the
space.
Be aware from enhancing vasa
vasorum and ptrygoid plexus of veins.
Here, enhancement around dark
nerve.

100. Retropharyngeal space:
SHN IHN

101. RPS

102. Non-abscess fluid:
 May be reactive to nearby pathology:
 IJV thrombosis.
 Longus colli tendinosis.
 Neck surgery.
 Early infection pre-abscess.
 General principle:
 Smooth expansion of the space without
enhancement.

103. DD from RPS abscess:

104. Abscess formation (RPS):
 < 6years or immunocompromised.
 Like abscess elsewhere.
 Tense fluid collection distending the
space with variable enhancement.

105. RPS: Lymphadenopathy:
 Benign: smooth homogeneous < 0.8cm.
 Malignant: oval to round mass with
occasional enhancement and possible
necrosis.

106. VISCRAL SPACE:

107. Hashimoto thyroiditis:
 Chronic autoimmune-mediated lymphocytic
inflammation of thyroid gland.
 Non-specific enlargement of the gland without
calcification or necrosis.
 CT scan:
 Diffuse non-specific enlargement.
 Hypodensity is typical finding.
 MRI:
 Non-specific finding with high signal during T2WI.

108. US
 Real time:
 Early Stages: Non-specific:
○ Enlarged Heterogeneous Hypoechoic gland.
○ Hypoechoic foci may be seen (micronodulation).
 Late: small hypoechoic heterogenous fibrotic
gland.
 Uncommon: focal disease within normal
gland.
 Color Doppler:
 Early: increased vascularity.
 Late: absent blood flow signal.

110. Multinodular goiter:
 Enlarged gland with multiple nodules.
 The gland is well marginated.
 Calcification, necrosis, cystic degeneration
and hemorrhage may be seen.
 US  shows cystic and solid nodules
 Hemorrhage may be seen as high echogenecities
 CT shows cystic and solid nodules with Ca.
 Hemorrhage may be seen as high densities.

113. Thyroid adenoma:
 Thyroid adenoma: (true neoplasm with
complete capsule): Single well defined
intrathyroid mass within normal gland.
 Adenomatous polyp: adenomatous
hyperplasia with incomplete capsule: less
distinct and may be multiple.

115. Malignant thyroid mass:
 Types:
 Differentiated carcinoma:
○ Papillary (70%).
○ Follicular and carcinoma (10%).
 Aggressive tumors:
○ Medullary carcinoma (5%).
○ Anaplastic carcinoma (5%).
 Others including lymphoma and metastasis
(10%).

116. Thyroid malignancy:
 Unfortunately the appearance of thyroid
malignancy is usually non-specific.
 Nodules with irregular margin or mass
invading surrounding structures should
alert for malignancy.
 60% of malignant nodules have irregular
border and also 45% of benign nodules
have irregular border.
 Calcifications:
 Microcalcifications  malignancy
 Egg shell calcifications  benignity.

117. Thyroid malignancy:
 Role of imaging:
 Evaluation of thyroid capsule integrity.
 Detection of infiltration of surrounding
structures.
 Identification of malignant lymph nodes.

118. Differentiated carcinoma:
 Invasive mass with
thyroid capsular
invasion and
metastatic lymph
nodes.
 Hypoechoic mostly
solid tumor but cystic
changes are seen in
follicular type

119. Malignant thyroid:
Medullary carcinoma Anaplastic carcinoma

120. Parathyroid gland:
Adenoma
 It is well defined small mass in expected location.
 Associated hyperparathyroidism.

122. Posterior cervical space:

123. Spinal accessory schwanoma:
Oblong well defined mass along the course of spinal
accessory nerve.