Marsupialisation for the treatment of unicystic ameloblastoma of the mandible: a long-term follow up of 116 cases.

Unicystic ameloblastoma is a unique histopathological type of ameloblastoma, and treatment is controversial. Marsupialisation is effective in reducing the size of cystic lesions and their complications. We have retrospectively analysed the clinical, histopathological, and prognostic data of affected patients who were treated by marsupialisation between 2003 and 2013 in three Chinese hospitals. Our aim was to evaluate the effects and prognosis, and the factors associated with outcome. A total of 116 patients with mandibular unicystic ameloblastomas were included, and 74, 26, and 16 patients were histopathologically classified as being luminal, intraluminal, and mural subtypes, respectively. Most responded well to marsupialisation, with an overall recurrence rate of 12%. Resorption of the root (p<0.001), perforation of the cortical bone (p=0.005), and histopathological subtype (p=0.013) were the main factors that predicted the outcome. Perforation of the cortical bone was the only reliable predictor of recurrence (p<0.001). Disease-free survival function curves indicated that patients with the mural subtype were at a higher risk of recurrence than patients with the other two subtypes (p=0.003). Poor outcomes of marsupialisation were treated surgically and, to date, no subsequent recurrences have been reported. Marsupialisation is effective for these patients, with a recurrence rate similar to that of radical treatment. The outcomes can be predicted using characteristics of the lesion such as resorption of the root, perforation of the cortical bone, and histopathological subtypes. However, additional studies are required to corroborate these findings.