eRadiograph Volume 7: Imaging of Oral Cavity | Page 18
Floor of mouth cancer
Floor of mouth cancers constitute 18% of all oral cavity squamous cell carcinomas.
They may extend superiorly to involve the ventral tongue inferiorly through
mylohyoid muscle into submandibular space, posteriorly into base of the tongue
anterior/antero laterally into mandible.
Lesions in the anterior floor of mouth may obstruct whartons duct and resultant
dilatation of the duct and enlargement of submandibular gland or sialadenitis. Infact,
floor of mouth lesions may be very small and easily missed but come to attention due
to involvement of whartons duct. Most floor of mouth cancers arise in the anterior 2
cm, the neuromuscular bundle runs very close to the midline, extension across the
midline to involve both near vascular bundles will necessitate a total glossectomy.
Involvement of mandibular cortex, extrinsic muscles of tongue, skin of face, masticator
space, ptyergoid or skull base constitute stage 4 disease. There may be lymphatic
dissemination to sub mental, sub mandibular and periparotid adenopathy.
RMT cancers constitute 7-12% of oral cavity cancers. They may extend anteriorly to
the buccal mucosa, gingiva, posteriorly to anterior tonsillar pillar, soft palate,
posterolaterally to masticator space.
Hard Palate
This is a thin horizontal bone which spans the arch formed by the palatine process of
the maxilla and horizontal plates of palatine bone. The arch is formed by the alveolar
ridges and upper teath. Posteriorly the hard palate is contigous with the soft palate.
The junction between hard palate and soft palate is also the junction between the oral
cavity and the oropharynx. It forms the roof of the oral cavity and the floor of the nasal
cavity. The greater palatine nerve runs through the greater palatine foramen, which is
located medial to the posterior third molar. This is a potential site of spread of tumor
along the branches of V2 into the ptyergopalatine fossa.The hard palate is well
depicted as a hypointense cortex and central hyperintense marrow. The hard palate is
rich in minor salivary glands. These may be seen along the inferior surface of hard
palate as enhancing foci. This is the reason minor salivary gland tumors are more
common in the hard palate than squamous cell carcinoma, which predominates in the
rest of the oral cavity. Adenocystic carcinoma, mucoepi dermoid carcinoma or
adenocarcinoma may occur. These tumors may invade the maxillary sinus, palatine
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Imaging of Oral Cavity
Alveolar Ridge Cancers
Upper alveolar ridge cancers may spread medially to the palate, maxillary sinus and
nasal cavity. Lower alveolar ridge cancers may extend medially to floor of mouth,
laterally to buccal space, masticator space. Since alveolar ridge cancers are close to
bone - bony involvement is common as well as perineurial spread alongwith inferior
alveolar nerve.