Ameloblastoma - Did you know?
Ameloblastoma is a benign odontogenic tumor. Though it follows a benign course, the tumor shows aggressive behaviour and is locally invasive.
Robinson defines this tumor as being ‘usually unicentric, nonfunctional, intermittent in growth, anatomically benign and clinically persistent’.
Though known to be the second most common odontogenic tumor, studies are increasingly showing ameloblastoma to be the most common odontogenic tumor in India.
🤔Did you know, the ameloblastoma subtypes have been reclassified?
Ameloblastoma - subtypes
Ameloblastoma was previously thought to comprise of the following subtypes
However, in the latest (4th) edition of the World Health Organization Classification of Head and Neck tumours, ameloblastoma subtypes include
💡The "Solid/multicystic" and "Desmoplastic" subtypes have been removed from the classification. "Metastasizing ameloblastoma" is the new subtype that has been included as a benign subtype of ameloblastoma.
🤨Wait a minute…
Isn’t “Metastasizing ameloblastoma” a malignant odontogenic tumor while ameloblastoma benign? How has it been included as a subtype of ameloblastoma, then?
Metastasizing ameloblastoma is defined as a histologically benign typical ameloblastoma which metastasises to distant sites. Both the primary lesion and the metastasis must have histological features of benign ameloblastoma.
- 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.
💡This is much like how “metastasizing pleomorphic adenoma” is considered to be a variant or a complication of pleomorphic adenoma.
🤔Why were the other 2 subtypes removed?
Solid/Multicystic - Most ameloblastomas are the “conventional type” and were synonymously called solid/multicystic. Conventional ameloblastoma is a well-recognized entity.
💡Moreover the term “multicystic” caused confusion with the unicystic variety. Hence the term “solid/multicystic” has been removed.
Desmoplastic - This was previously thought to be a distinct clinicopathologic entity by itself.
💡However, desmoplastic ameloblastoma, though histologically distinct does not show any difference in clinical behaviour from conventional ameloblastoma.
Hence this subtype has been removed and is now only considered to be a histological pattern of conventional ameloblastoma.
📖I would recommend going through the article, New tumour entities in the 4th edition of the World HealthOrganization Classification of Head and Neck tumours: odontogenic and maxillofacial bone tumours, by Paul M.Speight and Takashi Takata. The article takes you through the major changes that have been made recently, in the classifications of Odontogenic Cysts and Tumours.
🎥 A Preview Video!
🔎You could dig deeper into the topic
In fact, we delve a lot more deeper into this topic in our cheatsheet/note -> Ameloblastoma. We talk about,
Clinical, Radiology and Histopathology features
📖📽We have a separate note and video on the topic Metastasizing ameloblastoma & Ameloblastic carcinoma.
You could read in detail about Ameloblastoma with our Revision Ninja - Oral Pathology and Medicine Course bundle!
📽We have 3 videos on this topic,
Ameloblastoma - Clinical features, Radiology and Treatment
Metastasizing ameloblastoma & Ameloblastic carcinoma
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.
📚Other study resources on HackDentistry!
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Dr.Sanketh from Team HackDentistry