Lesions of the Mandible and Maxilla
Question and answer review of lesions of the mandible and maxilla for radiology and nuclear medicine board review.
Show Notes/Study Guide:
The number of lesions of the mandible and maxilla are extensive. This episode will focus on
several of the most common lesions of the mandible and maxilla as these common lesions are
also the lesions I believe are most likely to be tested on non-subspecialty radiology board
examinations which is beyond the scope of this episode. My advice is to not get lost in the weeds
when it comes to lesions of the mandible and maxilla and to first master the most common
lesions before you venture into uncommon pathology.
What are two of the most common odontogenic tumors?
The most common odontogenic tumors may be odontomas and ameloblastomas. An odontoma
is the most common odontogenic tumor of the mandible followed by ameloblastoma.
What is a common association with an odontoma?
Odontomas are associated with an unerupted tooth in approximately 50% of cases. Note also
that odontomas have a Gardner syndrome association. As a reminder Gardner syndrome is a
familial polyposis syndrome associated with things like osteomas, desmoid tumors,
fibromatoses and odontomas.
What are common imaging features of an odontoma?
Common imaging features of an odontoma include a lucent lesion of the mandible or maxilla
that over time shows calcifications that coalesce to form a dense lesion with a lucent rim. A
complex odontoma may show irregular calcifications with no distinct tooth and a compound
odontoma may show a lesion with tooth-like components.
Odontomas and ameloblastomas arise most commonly in which decade of life, respectively?
Odontomas arise most commonly in the 2nd decade of life and ameloblastomas arise most
commonly in the 3rd to 5th decades of life.
What is the most common location for an ameloblastoma?
Ameloblastomas most classically arise near the angle of the mandible but can less commonly be
seen elsewhere along the mandible or maxilla.
What are common imaging features of an ameloblastoma?
The majority of ameloblastomas show a multicystic or “soap-bubble” appearance which
appears as expansile cystic lesions with well-defined margins but some ameloblastomas may be
unilocular. Ameloblastomas are often locally aggressive so additional features such as tooth
resorption and cortical erosion through the bone into adjacent tissues may be seen. Less
commonly an ameloblastoma may show a unicystic appearance, appearing similar to other
lesions to include a dentigerous cyst. On MRI an ameloblastoma may show solid papillary
projections within the lesion that show avid enhancement which can be helpful for diagnosis.
1Lesions of the mandible and maxilla. Matt Covington, MD
Listen to the associated podcast episode(s) available at theradiologyreview.com or on your favorite
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Less commonly ameloblastomas may be malignant and show evidence of metastatic disease on
imaging. Signs of potential malignant transformation include cortical destruction, extraosseous
extension, aggressive growth, and large solid components.
What is the common imaging appearance of a dentigerous cyst on imaging?
First of all, a dentigerous cyst is also sometimes termed a follicular cyst. The classic appearance
of a dentigerous cyst is a unilocular lucent lesion surrounding the crown of an impacted or non-
erupted tooth in the mandible. It is said that imaging showing the crown of a tooth projecting in
to the cystic space is pathognomonic of a dentigerous cyst. On CT, fluid within the cyst cavity is
often water density. On MRI, dentigerous cysts follow water/CSF signal with low T1 and bright
T2 signal with no internal enhancement but possible thin peripheral enhancement.
What are some basic differences between a periapical cyst and a dentigerous cyst?
Periapical cysts are more common than dentigerous cysts. Dentigerous cysts are often
associated with the crown of an impacted or unerupted tooth and a periapical cyst is associated
with the roots of a tooth. A dentigerous cyst is related to fluid accumulation around an
unerupted tooth whereas a periapical cyst is often the result of a dental infection and an
associated dental cavity may be seen. Both often appear as a unilocular lucent lesion. Unlike a
periapical cyst, a dentigerous cyst can become very large. Dentigerous cysts have a low risk of
transformation into an ameloblastoma.
What are typical features of an odontogenic keratocyst?
Odontogenic keratocysts are classically destructive, multilocular lesions centered about the
ramus or body of the mandible. Unlike a dentigerous cyst, an odontogenic keratocyst can erode
through the cortex of the mandible and may have daughter cysts within the surrounding bone.
If you see multiple odontogenic keratocysts, basal cell nevus syndrome can be considered.
What are classic features of a juvenile ossifying fibroma?
This is a lesion most often seen in boys under around 15 years of age and is an aggressive tumor
that can be seen in the mandible or paranasal sinuses. A key feature is rapid growth.
If a patient with multiple myeloma of the mandible, or another mandibular malignancy,
presents with numbness of the chin, what is a potential etiology for this symptom?
Malignant involvement of the inferior alveolar nerve can cause chin numbness in the setting of
mandibular malignancy.
What are some of the most common primary tumors that metastasize to the mandible?
Common tumors that can metastasize to the mandible include primary breast, lung and renal
malignancies. The most common site for metastatic disease of the mandible is the posterior
2Lesions of the mandible and maxilla. Matt Covington, MD
Listen to the associated podcast episode(s) available at theradiologyreview.com or on your favorite
podcast directory.
body and angle as these have a robust blood supply. If you see a sclerotic metastases to the
mandible in a genetic male consider prostate cancer as well. Also remember that multiple
myeloma may show involvement of the mandible.
What is more common—metastatic disease to the mandible or metastatic disease to the
maxilla?
Metastatic disease to the mandible is much more common than metastatic disease to the
maxilla—something like 4x more common.
Multiple osteomas in the mandible have a classic association with what syndrome?
Gardner syndrome (familial colonic polyposis syndrome)
Osteonecrosis of the jaw is associated with what common therapy?
Bisphosphonate use has a classic association with osteonecrosis of the jaw. This results in
osseous destruction of the mandible more commonly than maxilla and may have exposed bone.
Other medications may also be associated with this entity to include things like denosumab
(RANKL inhibitor), tyrosine kinase, mTOR, and VEGF inhibitors.
If you see pronounced increased uptake diffusely involving the skull and mandible on a bone
scan what entity should you first consider?
Hyperparathyroidism is most classic for diffuse intense skull and mandibular uptake on a bone
scan on board exams although this imaging appearance can also be seen with other metabolic
bone disease.
If you only see diffuse bone scan uptake through the mandible but not the skull, what entity
is most likely on board exams?
Consider the possibility of Paget’s disease. Some call this the “black beard sign”. If mono-
ostotic that could be the only site of uptake. Other classic areas of uptake in polyostotic Paget’s
disease include the pelvis and femurs.
If only a portion of the mandible shows uptake on a bone scan what are top differential
considerations?
Fibrous dysplasia of the mandible is one common cause of bone scan uptake involving only a
portion of the mandible. Dental disease may also show focal mandibular uptake due to
inflammation with active bone remodeling. Metastatic disease may also be considered,
particularly if other sites of suspicious uptake are also noted on the bone scan.
For additional details and great images of dental and mandibular lesions please see this
RadioGraphics article: https://pubs.rsna.org/doi/full/10.1148/rg.266055189
