Mandible / maxilla
Benign tumors / tumor-like conditions
Ossifying fibroma




Topic Completed: 1 May 2018

Revised: 8 February 2019

Copyright: 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Ossifying fibroma mandible [title]

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Cite this page: Martinez A. Benign tumors / tumor-like conditions: ossifying fibroma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillaossifyingfibroma.html. Accessed February 18th, 2019.
Definition / general
  • Benign fibro-osseous neoplasm
  • Two general categories:
    • Ossifying fibroma (discussed in this topic)
    • Juvenile ossifying fibroma
  • Usually requires surgical excision
Essential features
Terminology
  • Cemento-ossifying fibroma
  • Cementifying fibroma
  • Periodontoma
Epidemiology
Sites
Pathophysiology
  • Largely unknown for sporadic ossifying fibroma
  • Can rarely show syndromic / inherited association:
    • Hyperparathyroidism jaw tumor syndrome (Head Neck Pathol 2014;8:432)
      • Rare autosomal dominant cause of familial hyperparathyroidism associated with ossifying fibromas of the maxillofacial bones and increased risk of parathyroid carcinoma
      • Putative tumor suppressor gene CDC73 on chromosome 1q31 implicated in the syndrome, with a multitude of inactivating mutations identified
      • Loss of function of tumor suppressor gene CDC73 results in premature truncation of parafibromin protein product
    • Familial gigantiform cementoma
      • Transmitted as an autosomal dominant trait that is fully penetrant but with variable expressivity
      • Molecular studies to characterize specific mutations are currently unavailable
      • Whether or not genetically related to gnathodiaphysial dysplasia is currently not known
    • Gnathodiaphysial dysplasia
      • GDD1 gene, also known as TMEM16E or anoctamin 5 (ANO5) is mapped to a locus on chromosome 11p14.3 - 15.1
      • High levels of GDD1 protein expression in normal cardiac and skeletal muscle tissue as well as in growth plate chondrocytes and osteoblasts in bone suggests an important role for GDD1 in the development of the musculoskeletal systems
Etiology
Clinical features
  • Sporadic (most common)
    • Painless expansion of buccal or lingual plates of jaw
    • Large lesions can expand the inferior mandibular border
    • Isolated lesion
  • Syndromic or Inherited
    • Hyperparathyroidism jaw tumor syndrome
      • Similar to ossifying fibroma, however may be multiple
      • Hyperparathyroidism
      • Risk for parathyroid carcinoma
    • Familial gigantiform cementoma
      • Multifocal / multiquadrant expansive lesions of the jaws, which can be massive and cause remarkable facial deformity
      • No other bones are affected
      • Lesions arise during childhood and progressively expand to cause facial deformity during early adult years
    • Gnathodiaphysial dysplasia
      • Multifocal / multiquadrant expansile cemento-ossifying fibroma lesions of the jaws which can be massive
      • Extragnathic skeletal abnormalities variably described as osteopenia, osteogenesis imperfecta, fragile and brittle bone disease that lead to multiple fractures, bowing and cortical thickening of the tubular bone
Diagnosis
  • Diagnosis dependent on clinical, radiologic and pathologic correlation
Radiology description
  • Expansile
  • Early lesions can be radiolucent but progressively more radiopaque over time
Radiology images

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Fractures in the zygomatic bone and mandibular lesion


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Mass filling the right nasal cavity with bony involvement and mild contrast uptake

Prognostic factors
  • Slow growing, benign neoplasm
  • Uncommon recurrence
Case reports
Treatment
Clinical images

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Large maxillary tumor

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Right mandible tumor

Gross description
  • Rubbery tan fragments with possible mineralization, gritty
Gross images

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Enucleated tumor

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Large maxillary tumor

Microscopic (histologic) description
  • Well defined and may be encapsulated
  • Usually has hypercellularity of stroma with mineralized matrix
    • Stromal fibroblastic cells have hyperchromatic nuclei; mitoses are not easily found
    • Matrix: may see woven and lamellar bone deposits or cementum-like calcifications distributed throughout the lesion
    • Scant osteoclasts
    • Calcified structures are composed of variable amounts of osteoid or bone and lobulated basophilic masses of cementum-like tissue resembling the cementicles that are normally found in the periodontal membrane; these structures may coalesce and form curvilinear trabeculae which may be acellular
  • Ratio of bone to cementum-like tissue varies; one or the other type of the calcified tissue may dominate
  • Under polarized light, Sharpy's fibers are seen to project radially from spheroidal deposits
Microscopic (histologic) images

Images hosted on PathOut server:

Contributed by Kelly Magliocca D.D.S., M.P.H.

Mandibular ossifying fibroma

Positive stains
Negative stains
Molecular / cytogenetics description
  • No GNAS mutation identified in ossifying fibroma
  • Hyperparathyroidism jaw tumor syndrome
    • Putative tumor suppressor gene CDC73 on chromosome 1q31 implicated in the syndrome, with a multitude of inactivating mutations identified
    • Loss of function of tumor suppressor gene CDC73 results in premature truncation of parafibromin protein product
  • Gnathodiaphysial dysplasia
    • GDD1 gene, also known as TMEM16E or anoctamin 5 (ANO5) is mapped to a locus on chromosome 11p14.3 - 15.1
Molecular / cytogenetics images

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CDC73 mutations in sporadic tumors

Differential diagnosis
  • Oral cavity/gingival lesion:
    • Peripheral ossifying fibroma:
      • Most commonly small, although the origin of massive lesions can be difficult to identify without the use cross sectional imaging (Ann Maxillofac Surg 2016;6:300)
      • Punctate mineralized spherules or frank ossification in stroma
      • Reactive lesion
      • Ulcerated or intact squamous mucosa
      • Underlying stroma with plump fibroblasts
  • Intraosseous lesion may be problematic to distinguish between entities below when sample consists of small and fragmented biopsy tissues: histologic distinction from ossifying fibroma is not always reliable, emphasizing the importance of radiographic correlation
  • Desmoplastic fibroma
  • Fibrous dysplasia
  • Intraosseous meningioma: rare
  • Juvenile ossifying fibroma
  • Low grade spindle cell sarcoma, NOS with associated reactive bone
  • Osteoblastoma
  • Reactive bone ("proliferative periostitis")
  • Sclerosing odontogenic carcinoma with associated reactive bone or associated fibro-osseous proliferation
  • Well differentiated osteosarcoma
    • Infiltrative, relatively hypocellular and consists of monomorphic, minimally atypical spindle cells that are usually arranged in fascicles
    • Tumor cells are intimately related to the surfaces of elongated trabeculae of neoplastic woven bone that lack osteoblastic rimming (Am J Surg Pathol 2010;34:1647)
Board review question #1
    Which of the following conditions is not typically associated with ossifying fibroma?

  1. Basal cell nevus syndrome
  2. Gigantiform familial cementoma
  3. Gnathodiaphysial dysplasia
  4. Hyperparathyroidism jaw tumor syndrome
Board review answer #1
A. Basal cell nevus syndrome is not associated with gnathic ossifying fibroma. It is associated with odontogenic keratocysts of the jaw.
Board review question #2
    What are the collagenous appearing fibers radially projecting from the mineralized deposits?

  1. Amianthoid fibers
  2. Osteoblasts
  3. Rosenthal fibers
  4. Sharpey's fibers
Board review answer #2
D. Sharpey's fibers

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