Cemento-Ossifying fibroma - Did you know?

Cemento-ossifying fibroma (COF) previously called “Ossifying-fibroma” is a tumor where there is proliferation of cellular (fibroblasts) fibrous tissue along with calcifications in the form of basophilic spherical masses (cementum-like material) & immature bone (osteoid) (hence cemento-ossifying fibroma). 

It is a true neoplasm, in that, it has a proliferative (growth) potential and can cause expansion of bone.

🤨 Did you know Oral Pathologists have classified this entity as a mesenchymal Odontogenic tumor?

After a lot of research and debate over the years, Oral Pathologists have classified this entity as a mesenchymal Odontogenic tumor! So much for being a lesion of the bone.

Ossifying fibroma - Recent classification

Well, lets not jump the gun. Ossifying fibroma has other variants called “trabecular juvenile ossifying fibroma” and “psammatoid juvenile ossifying fibroma”. These entities are very much fibro-osseous lesions!

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💡Keratocystic odontogenic tumor (KCOT) has been reclassified too!

Odontogenic keratocyst - Did you know?

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📝Recent updates on classification of Cemento-Ossifying fibroma

The most recent (2017) WHO classification considers ossifying fibroma (OF) in general to have three variants

• COF, considered to be odontogenic in origin, and

• Non-odontogenic variants called

  • Juvenile trabecular OF (JTOF),

  • Juvenile psammamatoid OF(JPOF).

I know things may be a little confusing here. The truth is, it actually is.

Reference

Speight PM, Takata T. New tumour entities in the 4th edition of the World Health Organization Classification of Head and Neck tumours: odontogenic and maxillofacial bone tumours. Virchows Arch. 2018 Mar;472(3):331-339.

El-Mofty SK. Fibro-osseous lesions of the craniofacial skeleton: an update. Head Neck Pathol.2014 ;8(4):432–444.

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Cemento-osseous dysplasia versus cemento-ossifying fibroma

To add to the fuel, fibro-osseous lesions, especially cemento-osseous dysplasia (COD) and cemento-ossifying fibroma (COF) can be confusing topics for students, since there are so many overlapping/similar features as well as differences between the two. In fact we have a nice table enumerating the differences between the two. You could read it with our Revision Ninja - Oral Pathology and Medicine Course bundle!

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📋Fun Question

A female patient was diagnosed with focal cemento-osseous dysplasia based on the clinical and radiographic features. After treatment of the lesion however, diagnosis was suspected to be cemento-ossifying fibroma and was sent for a microscopic analysis. As suspected the final diagnosis (after microscopy/histopathology) was cemento-ossifying fibroma. What made the surgeons suspect cemento-ossifying fibroma?

💡Remember that this scenario (question) is a contrived example to drive home a point, that being the intra-operative findings of the lesion.

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🎥 A Preview Video!

Note: This video was made before the recent updates and classification of cemento-ossifying fibroma(COF). Otherwise the clinical features, radiology and histopathology for the lesion remain the same.

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🔎You could dig deeper into the topic

In fact, we delve a lot more deeper into this topic in our cheatsheet/note -> Cemento-ossifying fibroma. We talk about,

• Recent classification of Ossifying fibroma

• Controversies with nomenclature and origin

• Clinical, radiology and histopathology features

• A note on the juvenile variants of Ossifying fibroma - Juvenile trabecular ossifying fibroma and Juvenile psammamatoid ossifying fibroma.

• Key differences and similarities between Cemento-ossifying fibroma and Cemento-osseous dysplasia (dealt as a separate cheatsheet/table).

You could read in detail about Cemento-ossifying fibroma with our Revision Ninja - Oral Pathology and Medicine Course bundle!

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💡Note

Apart from Notes, you could also get access to numerous MCQs and Videos with English captions/subtitles on various topics in Oral Pathology and Medicine.

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📚Other study resources on HackDentistry!

• Revision Ninja - Oral Histology (Notes, Videos & MCQs)

• Revision Ninja - Periodontics (Notes & MCQs)

• Question Bank (5000+ Questions)

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And hey, by the way, please do give HackDentistry a shout-out to your friends and colleagues, would you? Would really appreciate it! Cheers and happy reading :)

Best

Team HackDentistry

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