mandible and maxilla Flashcards
osteosarcoma in the mandible. more or less aggressive than in long bones?
less aggressive
mandibular osteosarc.
presents at an older age. less aggressive than osteosarcoma in the long bones
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.
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 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.
odontoma
ameleoblastoma
ameleoblastoma
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
basal cell nevus syndrome (blue nevus syndrome)
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 nonerupted 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.
35 yoF
left side painless maxillary swelling of long duration
dentigerous cyst
Dentigerous or follicular cysts are usually benign developmental cysts, related to unerupted teeth.
25M with long standing painless swelling of the upper lip
dentigerous cyst
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.
52-year-old-man with left-sided facial pain and recurrent episodes of sinusitis
Odontogenic sinusitis in a 52-year-old-man with left-sided facial pain and recurrent episodes of sinusitis. (a) Axial CT image shows a periapical lucency (arrow) related to the left maxillary second premolar. (b) Coronal CT image shows the periapical lucency (arrow) and total opacification of the left maxillary sinus. Note the well-preserved aeration of other visualized sinuses.
what is more common, peri-apical lucencies or dentigerous cysts?
peri-apical lucencies. More people get cavities than weird congetial crap
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.
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.
juvenile ossifying fibroma
13M with a rapidly enlarging mandibular mass. XR and Tc-99m MDP scan are shown.
Juvenille ossifying fibroma
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?
most common site in the mandible for metastasis
posterior 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.
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.
black beard/abe lincoln beard sign
PAGETS!
hpt
diffuse calvarial and mandibular uptake
striped tie
“beautiful scan” - can see bones all the way down to the feet and hands
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 monoostotic that could be the only site of uptake. Other classic areas of uptake in polyostotic Paget’s disease include the pelvis and femurs.
Black beard sign - Paget disease
If only a portion of the mandible shows uptake on a bone scan what are top differential considerations?
fibrous dysplasia
fibrous dysplasia
fibrous dysplasia of the mandible
fibrous dysplasia
osteomas
osteoma
75yoM
multiple myeloma
Pt with breast cancer
madndibular metastasis
osteonecrosis of the jaw - bisphosphonates
bisphosphonate osteonecrosis of the mandible - bisphosphonates
osteonecrosis of the jaw - bisphosphonates
