Ossifying fibroma

Ossifying fibroma

1. Benign fibroosseous neoplasm

   • jaws/craniofacial skeleton
     • May be associated w/ hyperparathyroidism-jaw tumor Sx

2. 3 clinicopathological variants

   • Odontogenic origin
     • Cemento-ossifying fibroma
       • 3rd-4th decades
       • Female
         • 5:1
       • eclusively in the tooth bearing areas of the mandible and maxilla
         • mandible
           • PM
           • M
       • Painless expansion of buccal and lingual plates
         • Macroscopy: well defined, shelled out relatively easily
       • Rx
         • Early
           • Radiolucent
         • Progressively
           • Radiopaque
       • Histo
         • well defined
         • Hypercellular fibroblastic stroma containing variable amounts of calcified structures
           • Calcified structures: composed of variable amounts of osteoid or bone and lobulated basophilic masses of cementum-like tissue
         • Stromal cells: hyperchromatic nuclei but no marked atypic
       • TX
         • Surgically excised conservatively
       • Benign
         • Slow growing
   • Juvenile
     • Juvenile trabecular ossifyng fibroma
       • rare
       • children/adolescents
         • 8.5-12 yrs
       • male/female
       • Maxilla
       • Extragnathic occurrence is extremely rare
       • Progressive and sometimes rapid expansion
         • Macroscopy: shows curvilinear haemorrhagic strands not seen in other types of OF
       • RX
         • Expansile
         • Fairly well demarcated
       • Histo
         • Unencapsulated but well-delineated border
         • Loose architecture
           • Hypercellular stroma composed of spindle cells w/ little collagen production
         • Osteoid
           • Develops directly from the fibrous stoma and forms long slender strands that have been likened to pain brush strokes
             • Irregular mineralization takes place at the centre of the strands, resulting in the production of immature bone trabecular
     • Juvenil psammomatoid ossifying fibroma
       • rare
       • 16-33 yrs
       • male/female
       • Predominantly the extragnathic craniofacial bones
         • periobital frontal
         • ethmoid
       • Bony expasions
       • Histo
         • Unencapsulated
         • Characterized by multiple small uniform ossicles (psammomatoid bodies) embedded in cellular stoma composed of spindle and stellate cells
           • Psammomatoid bodie
             • Basophilic
               • Resemblance to dental cementum

3. Marx 2º ed

   • Slow growing
     • Benign neoplasms
       • Early-radiolucent