Background and objective: A keratocystic odontogenic tumour (KCOT) is considered a benign neoplasm of odontogenic origin which may present an aggressive and infiltrative behavior leading to high recurrence rates. To date, various conservative or aggressive management strategies have been suggested as a method of treatment, such as: radical resection, enucleation and marsupialization. Decompression followed by delayed enucleation of the residual cyst has been used as a conservative treatment for large KCOT, minimizing the tumour size and limiting the extent of surgery with low morbidity and high success rates. The aim of the study was to describe the histopathological changes and its clinical and radiological correlation before and after decompression for management of KCOT.

Method: 16 KCOT biopsies before and after decompression were analyzed. The degree of inflammation and presence of corium papillae was assessed using hematoxilin and eosin (HE) staining and cell proliferation was assessed using Ki-67 and PCNA antibodies in all samples. Clinical and radiographic changes were analyzed. Statistical analysis was performed using Wilcoxon–Mann–Whitney test and P values less than 0.05 were considered significant.

Results: A statistically significant difference in increased inflammation and presence of papillae was found after decompression, but not in epithelial proliferation with Ki-67 and PCNA antibodies. Clinically the lesion size decreased and bone formation was observed on the Panoramic Radiography.

Conclusion: Based on the results obtained in the present study, decompression management increases inflammation and epithelial proliferation thus decreasing tumour size for a conservative secondary enucleation.

Key words : keratocystic odontogenic tumour; decompression; enucleation