August 2008
Dr Gerhard Steenkamp

A 6 year-old Staffordshire bullterrier presents with a mass in the left maxilla.  Radiography of the affected area shows bone lysis and you proceed to do a biopsy of this tumour.  The pathologist reports that the tumour is an acanthomatous epulis.

a) What is an epulis?
b) Are these lesions benign or neoplastic?
c) Where do these tumours originate?
d) What is the treatment of choice for these tumours?

Memo

a) An epulis according to the Dorlands Medical Dictionary is “a non-specific term applied to tumours and tumour-like masses of the gingiva”.  It therefore has no bearing on the potential malignancy or not of a gingival mass.

b) Acanthomatous epuli are malignant tumours that does infiltrate and destroy bone.  No case of distant metasteses has been documented as far as the authors are aware.

c) These tumours are classed as one of the odontogenic tumours.  It is therefore believed that they originate from the remnants of the tissue that was involved in the production of teeth.  These remnant cells that may be present in the gingiva are called the rests of Seres and those remnant cells of the Hertwig root sheath are called the rests of Malassez.  It is unclear if they originate from one of these groups of cells or from both.  Current research by the authors and co-workers are aimed at establishing the origin of these tumours.  In recent times they have also, mistakenly, been called ameloblastomas.

d) Surgical resection of these tumours is curative. As can be seen from the post-operative photos, minimal distortion of the face can be achieved.  The use of radiation to treat these tumours is controversial.  Although there are a number of reports advocating radiation there is also a report that showed the transformation of 4 cases of acanthomatous epuli to squamous cell carcinoma post-radiation.  This modality should be advocated with extreme caution.