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

Author: Anthony Martinez, M.D.
Editor: Kelly Magliocca D.D.S., M.P.H.

Revised: 11 July 2018, last major update May 2018

Copyright: (c) 2003-2018, PathologyOutlines.com, Inc.

PubMed Search: Ossifying fibroma mandible [title]

Cite this page: Martinez, A. Benign tumors / tumor-like conditions: ossifying fibroma. PathologyOutlines.com website. http://www.pathologyoutlines.com/topic/mandiblemaxillaossifyingfibroma.html. Accessed July 22nd, 2018.
Definition / general
  • Benign fibro-osseous neoplasm
  • Two general categories composed of three clinicopathological variants
    • Ossifying fibroma
    • Juvenile ossifying fibroma (two subtypes)
      • Juvenile trabecular ossifying fibroma (JTOF)
      • Juvenile psammomatoid ossifying fibroma (JPOF)
  • Usually requires treatment (surgical excision)
Essential features
Terminology
  • Ossifying fibroma
    • 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 (HPT-JT) (Head Neck Pathol 2014;8:432)
      • HPT-JT is 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 (FGC)
      • FGC is 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 FGC and GDD are genetically related is currently not known
    • Gnathodiaphysial dysplasia (GDD)
      • 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
  • Oral Dis 2017;23:440
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
  • Head Neck Pathol 2014;8:432
Diagnosis
  • Diagnosis dependent on clinical, radiologic and pathologic correlation
Radiology description
  • Expansile
  • Early lesions can be radiolucent but progressively more radiopaque over time
  • Figure 1 - 9 ossifying fibroma associated with Hyperparathyroidism jaw tumor syndrome (Insights Imaging 2016;7:793)
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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Fig A. curettage of lesion

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

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Fig B. enucleated lesion

Microscopic (histologic) description
  • Microscopically the tumor is well defined from bone and may be encapsulated
  • Varying, but usually hypercellularity of stroma with mineralized matrix
    • Stromal fibroblastic cells show hyperchromatic nuclei; mitoses are not easily found
    • Matrix: may see woven and lamellar bone deposits, and/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 the bone to the cementum-like tissue varies in different lesions; in some tumors one or the other type of the calcified tissue may dominate
  • Under polarized light, Sharpy's fibers are seen to project radially from these 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 (HPT-JT)
    • 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 (GDD)
    • GDD1 gene, also known as TMEM16E or anoctamin 5 (ANO5) is mapped to a locus on chromosome 11p14.3 - 15.1
  • (Mod Pathol 2013;26:1023)
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 OF is not always reliable, emphasizing the importance of radiographic correlation
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 (BCNS) is not associated with gnathic ossifying fibroma. BCNS 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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