Imaging of Palate Masses
Marin McDonald, MD PhD
Julie Bykowski, MD
ASNR Annual Meeting – Chicago 2015
Disclosures
•
The authors have nothing to disclose.
Educational goals and summary of cases
• Key cases will be used to define anatomy, regional vascular supply, drainage
and innervation, as well as indications and implications for surgical resection.
• Benign: pleomorphic adenoma, papilloma, benign osseous lesions.
hemangioma, necrotizing metaplasia, osteomyelitis
• Malignant: adenoid cystic carcinoma, mucoepidermoid carcinoma,
squamous cell, lymphoma and sarcoma
• Common imaging findings suggesting perineural and lymphangitic spread of
palate-based malignancies
• NCCN guidelines for diagnosis, evaluation and treatment.
Anatomy of the hard and soft palate
Soft palate
Nasal cavity
Nasopharynx
Hard palate
Oropharynx
tongue
Hypopharynx
epiglottis
trachea
trachea
esophagus
Adapted from instantanatomy.net
Anatomy of the hard and soft palate
incisive
fossa
Soft palate
Nasal
cavity
Nasopharynx
Hard
palate
Oropharynx
Palatine
plate
Horizontal
plate
tongue
Hypopharynx
epiglottis
trachea
trachea
esophagus
Greater and
lesser palatine
foramen
Soft
palate
Tensor and
Levator veli
palatini
Adapted from instantanatomy.net
Anatomy of the hard and soft palate
• Hard palate: anterior 2/3
• Thick mucosa covered by
ketanized stratified squamous
epithelium
• Minor salivary glands
predominant along posterior
margin
• Soft palate: posterior 1/3
• Formed by connective tissue, the
glosspalatine and
pharyngopalatine muscles
• Covered by nonkeratinized
squamous mucosa
• Mobility via tensor and levator veli
palatini
incisive
fossa
Palatine
plate
Horizontal
plate
Greater and
lesser palatine
foramen
Soft
palate
Tensor and
Levator veli
palatini
Tumors of the palate
•
Benign and malignant palatal tumors are usually
asymptomatic masses that are occasionally
associated with a low level of discomfort.
• Up to 50% of hard palate tumors are locally
spread at time of presentaton
•
Standard evaluation includes:
• Full head and neck exam
• Trismus  oropharyngeal involvement
• Masseter wasting -> maxilary PNI
• Palatal hyperesthesia -> maxillary PNI
•
CT – extent of tumor burden, osseous invasion
•
MR – soft tissue evaluation, PNI
•
FNA/excision
Benign palate masses
• Represent ~ 50% of all palate based tumors
• Most common salivary type – pleomorphic adenoma
• Most common epithelial type – papilloma
• Others including
•
•
•
•
Benign osseous lesions
Mucopideroid
Hemangioma
Necrotizing metaplasia
Palate masses: pleomorphic adenoma
• Most common type of salivary gland tumor
of the palate
•Commonly located lateral to the midline of
the posterior hard palate.
• Painless, firm or rubbery, slow-growing,
well-delineated masses that are covered with
normal mucous membranes
• Fibrous capsules appearing as hypointense
on T2-weighted images with characteristic
delayed enhancement
Palate masses : benign osseous lesions
Torus palatini
•
Developmental exostosis that
arises from the midline of the
hard palate.
•
Classified as flat, nodular,
lobular or spindle types
•
Replacement of normal bone
with fibrous connective tissue
•
Expansile lesions with groundglass opacity
Fibrous dysplasia
Palate masses: papilloma
• Benign epithelial tumor composed of squamous epithelium
• HPV subtypes 6 and 11 identified in up to 50% of oral papillomas
39 y/o M presenting with an intranasal mass
Palate masses: papilloma (natural history of …)
CT noncontrast 2007
CT noncontrast 2011 (concerning for malignant degeneration, but pathology
consistent with inverted papilloma w/o dysplasia)
Palate masses: hemangioma
• Vascular anomalies are classified as infantile
hemangiomas and vascular malformations
(capillary, venous, lymphatic, and arteriovenous
types)
• On T2-weighted images, generally appear as
multiple hyperintense lobules (“bunch of grapes”)
Anatomy of the hard and soft palate
• Blood supply: from the maxillary artery
via the descending palatine artery
• Hard palate: greater palatine
artery
• Soft palate: lesser palatine artery
•Venous drainage: pterygoid plexus
Greater palatine
foramen
Incisive
fossa
lesser palatine
foramen
Nasopalatine
nerve
Greater palatine
artery
Greater palatine
nerve
Lesser palatine
arteries
Lesser palatine
nerves
Adapted from instantanatomy.net
Necrotizing sialometaplasia
24 y/o otherwise healthy female with new lesion on roof of mouth
• Nonneoplastic inflammatory condition of the salivary glands, with over
75% occurring on the palate
• Underlying etiology thought to be related to ischemia, typically present as
a crateriform ulcer of the palate that spontaneously resolves
• Often not seen on imaging
Palate masses - malignant
• Represent about half of all palate based tumors
• Different spectrum of tumor pathology based
on location
• Hard palate – minor salivary gland malignances
(e.g. mucoepidermoid)
• Soft palate – majority squamous cell carcinoma
• Varied patterns of spread require multidisciplinary
approach to diagnosis
• Full H/N exam (mastoid effusion? Nasosinal
disease? Absent masseteric reflex?)
• CT to evaluate for osseous invasion, lymphatic
involvement
• MR to improve resolution of PNI
• Local excision/punch biopsy for pathology
Tumors of the palate: size matters
•Staging of primary tumor (T)
•T0 - carcinoma in situ
•T1 - Tumor <2 cm
•T2 - Tumor larger > 2 cm but < 4 cm
•T3 - Tumor > 4cm
•T4 – local invasion
Tumors of the palate: size matters
•Staging of primary tumor (T)
•T0 - carcinoma in situ
•T1 - Tumor <2 cm
•T2 - Tumor larger > 2 cm but < 4 cm
•T3 - Tumor > 4cm
•T4 – local invasion
•Diagnosis: Mucoepidermoid
•1.5% of all salivary gland tumors
•Presents as a well-circumscribed mass with smooth or lobulated margins
• Various degrees of enhancement
Tumors of the palate: size matters
•Staging of primary tumor (T)
•T0 - carcinoma in situ
•T1 - Tumor <2 cm
•T2 - Tumor larger > 2 cm but < 4 cm
•T3 - Tumor > 4cm
•T4 – local invasion
• Diagnosis: Adenoid cystic carcinoma, T3
• Most common salivary gland malignancy in the palate
• Can appear either as a benign or malignant lesion
• High-grade tumors have a proclivity for bone invasion
Tumors of the palate: size matters
•Staging of primary tumor (T)
•T0 - carcinoma in situ
•T1 - Tumor <2 cm
•T2 - Tumor larger > 2 cm but < 4 cm
•T3 - Tumor > 4cm
•T4 – local invasion
• Diagnosis: Invasive squamous cell carcinoma, T4
• Approximately half of all palatal malignancies are SCCs
•up to 50% hard palate malignancies, 80% soft palate lesions
• Extension beyond the hard palate occurs in up to 70% of lesions
at presentation
Tumors of the palate: size matters
•Staging of primary tumor (T)
•T0 - carcinoma in situ
•T1 - Tumor <2 cm
•T2 - Tumor larger > 2 cm but < 4 cm
•T3 - Tumor > 4cm
•T4 – local invasion
• Diagnosis: adenoid cystic carcinoma with perineural
invasion, T4
•High-grade tumors have a proclivity for perineural spread along
the greater and lesser palatine nerves, followed by extension to
the pterygopalatine fossa and cavernous sinus
Tumors of the palate: perineural spread
intracranial
PGP
fossa
Infraorbital
canal
Infraorbital nerve
Superior alveolar nerves
CNV ganglion
Lesser palatine nerve
Nasopalatine nerve
Greater palatine nerve
Adapted from teachmeanatomy.net
face
Tumors of the palate: perineural spread
Subtle widening of the right greater palatine foramen (left) is the only indicated
on CT of perineural invasion, later confirmed on MRI with gadolinium.
Thickening and enhancement of the right greater palatine nerve (center)
confirms perineural spread of the patient’s adenoid cystic carcinoma, which
extends cephalad towards the pteropalatine gangion (right).
Special cases: Polymorphous low-grade adenocarcinoma
• Rare type of salivary gland malignancy, most common site is the hard or
soft palate
• Asymptomatic, slow-growing masses that are covered by nonulcerated
mucosa
• Imaging features of PLGA are nonspecific.
•potentially cause bone resorption, medullary infiltration, and invasion
of nearby nerves and blood vessels
•Metastasis to a lymph node are extraordinarily rare
Special cases: lymphoma
44 M with ALL and new onset trismus
• Approximately 20% of oral non-Hodgkin lymphomas occur in the
palate
• Commonly arise at the junction of the hard and soft palate.
• B-cell non-Hodgkin lymphomas
• Can present either an expansile or destructive growth pattern ,
often with associated lymphadenopathy
Tumors of the palate: lymphatic spread and staging
I
•Lymphatic involvement can be assessed
by either CT or MR
III
•Most commonly seen in SCCs and high
grade mucoepidermoid tumors, soft
palate >>hard palate
•Up to 30% soft palate with
lymphatic spread on presentation
II
V
IV
•Predilection for:
•Retropharyngeal (particularly with
posterior extension of soft palate
SCCs)
•Level I
•Level II
Special cases: lymphoma
12/27/2013
4/3/2014 (s/p chemoradiation)
Special cases: osteomyelitis
CT 12/3/2012
CT 4/6/2012
56 M diabetic with invasive fundal sinusitis, status post left orbital
exteneration and sphenoidectomy. CT 4/6/4012 demonstrates extensive
interval erosion of the hard palate with ill-defined heterogenously enhancing
phlegmon, compatible with osteomyelitis of the hard palate.
Special cases: recurrence
43 F status post resection of prior left palatal SCC with resection of left
mandibular body, left maxilla and flap reconstruction. New soft tissue thickening
and enhancement along the left posterior nasopharynx and oropharynx extending
to the left parapharyngeal space, later biopsy proven recurrent veruccous SCC
Special cases: sarcoma
30 month old female with left sided facial swelling and proptosis
On CT, ill-defined mass
centered within the left maxilla
and hard palate with extension
into the left maxillary sinus and
orbital floor (top left). Significant
widening and soft tissue
extension of the left
infraorbital foramen concerning
for perineural spread (top right),
confirmed on subsequent MRI
by enhacenement nad thickeing
of the left infraorbital nerve
(bottom right).
Diagnosis: melanotic
neuroectodermal tumor of
infancy (MNTI)
Conclusion
• Think beyond squamous cell carcinoma when approaching palatal masses
• Over 50% of malignant lesions present with local spread at presentation,
making clinical history and adjunctive imaging of critical importance
• Soft palate SCCs have a much higher predilection for lymph node spread than
salivary gland malignancies/hard palate tumors
• Subtle changes such as palatine foramina widening may be the first indicated
of PNI
• A multidisciplinary approach is crucial for the staging and treatment of palate
malignancies
Self-assessment #1
A. The yellow arrow in the figure #1 is
indicating which anatomic structure?
1. The incisive foramen
2. The greater palatine foramen
3. The lesser palatine foramen
Fig. 1
Self-assessment #1
A. The yellow arrow in the figure #1 is
indicating which anatomic structure?
Fig. 1
1. The incisive foramen
2. The greater palatine foramen
3. The lesser palatine foramen
The yellow arrow highlights the greater palatine foramen, the entry point of
greater palatine nerve, which supplies sensory innervation to the hard
palate
Self-assessment #2
Fig. 1
In comparison to the above case, what
does the appearance of the greater
palatine foramen in figure 2 suggest?
1.
2.
3.
Perineural spread
Osseous invasion
Lymphatic spread
Fig. 2
Self-assessment #2
Fig. 1
In comparison to the above case, what
does the appearance of the greater
palatine foramen in figure 2 suggest?
1.
2.
3.
Perineural spread
Osseous invasion
Lymphatic spread
The yellow arrow highlights the greater palatine
foramen, the entry point of greater palatine nerve,
which supplies sensory innervation to the hard
palate
Fig. 2
Self-assessment #3
What stage is this hard palate tumor?
1.
2.
3.
4.
T1
T2
T3
T4
5.2 cm
Self-assessment #3
What stage is this hard palate tumor?
1.
2.
3.
4.
T1
T2
T3
T4
Staging of primary tumor (T)
T0 - carcinoma in situ
T1 - Tumor <2 cm
T2 - Tumor larger > 2 cm but < 4 cm
T3 - Tumor > 4cm
T4 – local invasion
In the absence of osseous invasion,
the 5.2 cm tumor is a stage T3.
5.2 cm
References
•
•
•
•
CT and MR imaging findings of hard palate tumrs. Kato H, Kanematsu M, Makita H,
Kato K, Hatakeyama D, Shibata T, Mizuta K, Aoki M.
Imaging of Perineural Tumor Spread from Palatal Carcinoma Lawrence E. Ginsberg
and Franco DeMonte AJNR Am J Neuroradiol 19:1417–1422, September 1998
Cervical metastases from squamous cell carcinoma of hard palate and maxillary
alveolus: A retrospective study of 10 years. Yang Z, Deng R, Sun G, Huang X, Tang E.
Head Neck. Jun 4 2013
Malignant neoplasms of the hard palate and upper alveolar ridge. Petruzzelli GJ, Myers
EN. Oncology (Huntingt). Apr 1994;8(4):43-8