Florid Osseous Dysplasia
Synonym / Acronym
Florid cemento-osseous dysplasia, gigantiform cementoma, familial multiple cementomas, diffuse cementosis, multiple enostosis, chronic sclerosing cementosis / FOD
Florid osseous dysplasia is the multiple form of PCD. The lesion is composed of multiple dense radiopacities where normal bone has been replaced by dense, acellular cemento-osseous tissue embedded and surrounded by peripheral rims of fibrous connective tissue. The lesion is more prone for infection due to its low vascular supply. There is no clear say when to consider PCD as FOD. However, the lesion is considered florid osseous dysplasia if it affected 3 or more quadrants of jaws or if it was extensive throughout single jaw.
Since FOD is the multiple form of PCD. It shares almost all of PCD features like: age, sex, ethnicity, histologic, and radiographic features. Women, especially Black and Asian women, are more commonly affected than men. The mean age is considered to be 42 years old; however, the age range is broad. FOD is asymptomatic most of the time unless secondary osteomyelitis is present. It is usually discovered incidentally during routine dental radiographic examination. Teeth associated with FOD are vital. There is no bone expansion usually unless if lesions were large.
FOD appears as well-defined mixed (radiolucent-radiopaque) or totally radiopaque and has a radiolucent periphery and surrounding sclerosing border similar to PCD. It can be involve both jaws bilaterally. However, it affects mainly the posterior mandible and occurs above the mandibular canal. The fibrous capsule can be difficult to be seen in mature lesions. Small radiolucent areas may represent simple bone cyst and they usually tend to enlarge. The radiopaque appearance of FOD has a “cotton wool” appearance or large amorphous regions of calcifications similar to the calcifications seen in PCD. Large FOD lesions can displace cortical plates, floor of the maxillary sinus superiorly and the mandibular canal inferiorly. Teeth adjacent to FOD can have hypercementosis that is fused to the lesion which render their extraction difficult.
Since FOD occurs bilaterally, affects multiple quadrants, and associated with the alveolar process helps in differentiating it from other lesions like Paget’s disease. Paget’s disease can have cotton wool radiopacity appearance and hypercementosis of teeth. However, Paget’s disease affects multiple bones (polyostotic) other than the mandible; while FOD affect areas above the mandibular canal in the alveolar process region. Chronic osteomyelitis sometimes has similar appearance to FOD. The cementum areas associated with FOD can be confused with bone sequestrum in osteomyelitis and the fact that FOD may have secondary osteomyelitis can further complicates differentiate it from chronic osteomyelitis.
Usually no treatment is necessary for FOD. It might be useful to have a panoramic radiograph to establish the extension of the lesion. FOD differs from fibrous dysplasia in its ability for continuous growth. Patients are asked to maintain a good oral hygiene as FOD can get infected causing secondary osteomyelitis. That is one of the reasons why care should be done when extracting teeth associated with the lesion to avoid secondary infection to the underlying FOD. Tooth extraction in the affected area exposes the avascular cementum to the oral cavity. Avascular cementum is susceptible to infection and may lead to chronic osteomyelitis with draining fistula tract. Severe atrophy of the mandible can cause avascular cementum masses to interfere with prosthetic dentures and may result in osteomyelitis. In this case, the cementum masses will get transformed into large bony sequestra. Patients having FOD and undergoing prosthetic should be considered to have their cementum level reduced before starting prosthetic treatment.
HISTORY: A 52-year-old female was referred for a Cone Beam CT scan for evaluation of radiopaque lesions in her mandible.
FINDINGS: There are multiple mixed lesions in mandible. The lesions appear to be associated with tooth #19 and endodontically treated tooth #30. The lesions appear to coalesce. They have a radiopaque center and surrounded by a thin radiolucent outline and sclerotic borders.
IMPRESSION: The radiographic signs are consistent with florid osseous dysplasia. If the periapical radiopacities persist in future radiographic exams and the patient remained asymptomatic, then root canal therapy would likely not be necessary. If the she required dentoalveolar surgery in the future that she may heal very slowly.