Treatment of the keratocystic odontogenic tumour (KCOT) generates discussion and controversy. What is appropriate treatment? What is an acceptable recurrence rate when considering treatment options? How can recurrence rates be reduced?

When considering minimally invasive approaches to the KCOT, both diagnostic manoeuvres and treatment variations need to be discussed. In the diagnostic realm, our department has expanded the use of fine needle aspiration biopsy techniques (FNAB) to include the sampling of tissue from intrabony pathology and report good success in distinguishing the KCOT from other odontogenic cystic and solid lesions. The modifications in standard FNAB technique ensuring the presence of epithelial cells will be discussed.

Various epithelial markers have been identified in the lining of the KCOT. In particular, more ordered and cornified epithelial lining produces low molecular weight keratins in abundance. A characteristic band-like uptake of anti-cytokeratin-10 antibodies is nicely demonstrated in the OKC lining. We have combined the use of FNAB and immunocytochemical staining for cytokeratin-10 to improve the accuracy of the biopsy and serve as a marker for changes in the keratin profile of the lining as cysts are being treated.

Decompression and longitudinal irrigation of the KCOT is not a newly described treatment although recent review papers have demonstrated a low rate of recurrence with this technique. We have also demonstrated a pattern of epithelial dedifferentiation as cystic lesions undergo this treatment. Cytokeratin-10 profiles change longitudinally and may well account for the low rate of recurrence. Our institutional experience with this technique will be presented.