Role of imaging in oral cavity cancer.

1. IMAGING OF ORAL CAVITY
CANCER.
PRESENTED BY: Dr. SHIVENDU SHEKHAR
PG II YR
DEPTT. OF RADIODIAGNOSIS, GMC
JAMMU.

2. ORAL CAVITY
• Most anterior subdivision of the aerodigestive tract.
• Oral cavity separated from oropharynx:
 circumvallate papillae/sulcus terminalis.
 anterior tonsillar pillars.
 soft palate/hard palate junction.

3. ORAL CAVITY
• Anteriorly : lips
• Laterally: buccal mucosa.
• Inferiorly: Floor of mouth-
Formed by myelohyoid muscle

5. • Oral cavity is divided into a central part ‘oral cavity proper’ and a lateral
part ‘the vestibule’.
• The oral cavity proper consists of oral tongue, roof formed by hard palate,
lateral walls by upper and lower alveolar ridges covered by gingival mucosa,
and the floor, formed chiefly by myelohyoid muscle.
• Vestibule is a cleft lined by buccal mucosa laterally and gingival mucosa
medially.

7. SUBSITES
• Lips
• Buccal mucosa.
• Upper and lower alveolar ridge.
• Retromolar trigone.
• Hard palate.
• Oral tongue.
• Floor of mouth(FOM).

8. RETROMOLAR TRIGONE (RMT)
• Mucosal fold extending behind the last mandibular molar up to the
last maxillary molar on either side.
• Triangular shaped, with base behind the mandibular last molar and
apex at the maxillary tuberosity.
• On CT images, RMT is seen in two or three consecutive axial sections.
• Seen in entirety in reformatted oblique plane.
• Pterygomandibular raphe(PMR) lie just beneath the mucosa of RMT.

10. PTERYGOMANDIBULAR RAPHE (PMR)
• Fibrous band-connects the posterior myelohyoid line of mandible to
the humulus of medial pterygoid plate.
• Serves as a route of tumor spread superiorly from RMT to pterygoid
process, anteriorly to buccal space and posteriorly to oropharynx.

11. GINGIVA
• Mucosa covering the alveolar rideges.
-buccal (lateral)
-lingual(medial)
• Gingivobuccal sulcus-junction between gingival and buccal mucosal
lining the check.

13. HARD PALATE
• Posteriorly-contiguous with soft palate(oropharynx subsite).
• Superior margin of oral cavity.
• Thin horizontal bone formed by:
 palatine process of maxilla.
 palatine bone horizontal plate.

15. HARD PALATE
• The greater palatine foramen is located medial to the posterior third
molar within the lateral border of bony plate.
• The greater palatine nerve runs through this foramen.
• Perineural spread of tumor into the pterygopalatine fossa.

17. ORAL TONGUE
• Anterior 2/3 of the tongue.
• Posterior 1/3 of tongue (base) is part of oropharynx.
• Intrinsic tongue musculature: four interdigitating superior and
inferior longitudinal, transverse and oblique muscles.
• Extrinsic tongue musculature: Genioglossus, Hyoglossus, Styloglossus
and palatoglossus.

21. FLOOR OF MOUTH
• MYELOHYOID:
 Forms the inferior border of FOM.
 Arises from the myelohyoid line of mandible, inserts into the hyoid
bone.
 U shaped sling, best appreciated on coronal plane.
 Separate oral cavity from submandibular space.

23. SUBLINGUAL SPACE
• Seen superomedial to myelohyoid and lateral to genioglossus.
• Contents: sublingual gland, deep part of submandibular gland, lingual
nerve and vessels and hyoglossus fibres.
• On CT, appears low density area while on MRI, seen as hyperintense
area.

24. BUCCAL SPACE
• Boundaries:
Medially: Buccinator.
Laterally: Zygomaticus major.
Posteriorly: Masseter.
• Contents: Buccal fat, angular branch of facial artery, facial vein, buccal
artery and parotid duct.
• Importance: SCC arising from buccal mucosa can spread to this region and
beyond into the masticator space.

26. ORAL CAVITY CANCER
• 30% of all malignant tumors of head and neck.
• 90% are squamous cell carcinomas(SCC).
• 10% minor salivary gland neoplasms
o melanoma
o lymphoma
o odontogenic tumors.

27. SQUAMOUS CELL CARCINOMA
• RISK FACTORS:
 Most common: prolonged use of alcohol and tobacco.
 Most common in India: Betel nut chewing, 45% of cancers in India.
 Leukoplakia and eryhtroplakia.
 HPV-minority.
• SITE:
 Worldwide: tongue(m/c)
 India: buccal mucosa(m/c).

28. • Small superficial lesions are often not visible on both CT and MR
images.
• With increasing size, the SCC infiltrate deeper submucosal structures.
• As a result, CT & MR show tumor mass and allow accurate evaluation
of deep tumor infiltration.

29. ROLE OF
IMAGING
DIAGNOSIS AND
STAGING
TREATMENT
PLANNING
RESPONSE
EVALUATION
RECURRENCE
DETECTION

30. MODALITY ADVANTAGE DISADVANTAGE
MDCT • EXCELLENT
ANATOMICAL DETAIL.
• SOFT TISSUE EXTENT.
• BONE EROSION.
• DENTAL AMALGAM
ATREFACTS.
• PERINEURAL SPREAD.
MRI • BEST FOR SOFT TISSUE
EXTENT.
• BONE MARROW
INVOLVEMENT.
• PERINEURAL SPEAD.
• LIMITED AVAILIBILTY.
• MAY OVERESTIMATE
BONE MARROW
INVASION AND
PERINEURAL SPREAD.
USG- LIMITED ROLE.
 TUMOR THICKNESS.
 NODAL INVOLVMENT.
 FNAC/BIOPSY.

31. AJCC STAGING OF ORAL CAVITY CANCER.

32. DEPTH OF INVASION

33. GINGIVOBUCCAL AND RMT SCC
• SCC of lower gingivobuccal complex are the most common oral cancer
in Indian subcontinent.
• Important issues that have an impact on management and prognosis
include soft tissue extent, bone erosion and nodal involvement.
• CT is preferred for Bone erosion while MR is preferred for assessment
of soft tissue extent.
• Puffed cheek maneuver on CT for better visualization.

35. SOFT TISSUE EXTENSION
• Laterally: buccal space.
• Superiorly: maxillary sinus.
• Medially: can erode the mandible and extend across into the lingual
musculature.
• Posterosuperiorly: into the masticator space.

37. POSTEROSUPERIOR SPREAD.
• Involvement of masticator space (T4b).
• Mandibular notch between coronoid process and condyloid process is used as
line of demarcation and classifies the disease as supra-notch and infra-notch
disease.
• Supranotch space contains lateral pterygoid muscle and upper 2/3 of
pterygoid plates.
• Infranotch space contains medial pterygoid and masseter muscle.
• Infranotch disease have more favorable prognosis as compared to
supranotch disease.

39. ROUTE OF SPREAD IN CA RMT

40. PERINEURAL SPREAD
• Through involvement of branches of mandibular nerve.
• Foraminal enlargement.
• Replacement of normal fat within the neural foramen.
• Enlarged nerve with enhancement on post contrast imaging (MRI)

42. BONY INVOLVEMENT AND ROLE OF
IMAGING
• Bone erosion is an adverse prognostic criterion.
• Preoperative imaging needs to comment on absence or presence of
mandibular erosion, whether subtle or gross and if marrow and
inferior alveolar canal are invaded.
• Marginal mandibulectomy is done when subtle erosion is present
while segmental mandibulectomy is done when there is gross erosion
or invasion of inferior alveolar canal.

43. CT FINDINGS OF BONY INVOLVEMENT
• Cortical erosions adjacent to the primary tumor.
• Aggressive periosteal reaction.
• Abnormal attenuation in bone marrow.
• Pathological fractures.

44. MRI FINDINGS OF BONY INVOLVMENT
• Loss of low signal intensity cortex.
• Replacement of high signal intensity marrow on T1 WI by
intermediate to low signal intensity.
• Contrast enhancement within the bone.
• Contrast enhancement of the nerves traversing the bone.

46. TONGUE AND FLOOR OF MOUTH SCC
• Majority of oral tongue SCC arise from the lateral border.
• MRI is modality of choice displaying excellent anatomical detail and
soft tissue extension.
• CT has insufficient soft tissue characterization and is hampered by
dental artefacts.
• Bone erosion is seen less frequently than in buccal cancers.

47. • Non contrast T1WI demonstrate cortical erosion and marrow invasion.
• Contrast enhanced T1WI help assess marrow invasion, perineural
spread, soft tissue extent, depth of invasion.
• T2 WI depicts extrinsic muscle and Floor of mouth involvement.
• Diffusion weighted imaging provides added value in lymph node
assessment.

48. MRI
• FEATURES OF MALIGNANCY:
HYPERINTENSE TO MUSCLE ON T2 WI AND STIR.
HYPO- TO ISOINTENSE TO MUSCLE ON T1 WI.
HETEROGENOUS ENHANCEMENT ON CONTRAST T1 WI.

50. FACTORS WITH PROGNOSTIC IMPORTANCE:
Extension to the extrinsic muscles.
Encasement of neurovascular bundle.
Invasion of floor of mouth.
Posterior extension involving base of tongue.
Extension of primary tumor up to or across midline.
Imaging can also assist plan adequate reconstruction after resection.

54. CA LIP WITH BONY EROSION

55. CA HARD PALATE WITH PERINEURAL
EXTENSION

56. NECK NODE METASTASIS
• Large proportion of oral cancers manifest initially as neck mass
representing cervical lymph node involvement.
• Single most important prognostic indicator.
• Level I & II nodes are often the first to be involved.
• Skip metastases with tongue cancers to Level III and IV and to
contralateral Level I and II.

57. • Nodal involvement vary according to anatomic subsite.
• Ca Retromolar trigone and floor of mouth: 50% incidence.
• Ca Oral tongue: 40% incidence.
• Ca Lips, buccal mucosa, hard palate: 10% incidence.
• In case of Ca Lip, involvement is often bilateral.
• Circumferential contact of involved node with carotid artery of more
than 270 degrees precludes resectability.

58. LYMPH NODE LEVELS OF NECK

59. USG
• FEATURES OF MALIGNANT LYMPH NODES:
INCREASE IN SIZE.
NODAL PARENCHYMA SHOWS INHOMOGENOUS LOW OR
MIXED ECHOGENCITY.
IRREGULAR MARGINS WITH ROUNED SHAPE.
LOSS OF NORMAL HILAR ECHOGENCITY.
COLOR DOPPLER: PERIPHERAL OR MIXED VASCULAR
PATTERN.
HIGH RESISTANCE WAVEFORM.(RI>0.8, PI>1.5)

61. CECT
• FEATURES OF MALIGNANT LYMPH NODES:
ENLARGED IN SIZE.
SPHERICAL IN SHAPE.
HETEROGENOUS ENHANCING PATTERN.
CENTRAL NECROSIS: HYPODENSE.
ILL DEFINED MARGINS

63. MRI
• FEATURES OF MALIGNANT LYMPH NODES:
INTERMEDIATE TO HIGH SIGNAL ON T2 WI.
HETEROGENOUS CONTRAST UPTAKE.
DIFFUSION RESTRICTION ON DWI.

65. EXTRACAPSULAR SPREAD
• 4 Fold increase in local recurrence rate.
• CT:
Poorly defined nodal margins.
Surrounding soft tissue stranding.
• MRI(T1-PC):
Poorly defined nodal margins.
Flare sign: High signal intensity in surrounding tissues.
Irregular rim like enhancement of the node.

66. CHECKLIST…
Soft tissue extent.
Bone erosion.
Masticator space disease.
Perineural extension.
Tumor depth of invasion-tongue cancers.
Posterior extent.
Nodal disease.

67. KEY TAKEAWAYS…..
Knowledge of anatomy coupled with spread patterns enables a
clinically relevant report.
Particular attention to issues of bone erosion and perineural spread
since these significantly influence the treatment options.
While MRI is superior to CT in delineation of soft tissue extent and
perineural disease spread, CT is preferred to assess bone erosion.

68. THANK YOU