Recurrent tumours of ameloblastoma: Clinicopathologic features and diagnostic outcome

Ameloblastoma is a benign epithelial odontogenic tumor with a tendency for recurrence. The recurrent tumors behave unpredictably with atypical microscopic changes and likelihood of malignant transformation.

To study the clinicopathologic features and diagnostic outcome of recurrent tumors of ameloblastoma in Enugu. This is a six-year (2012-2017) retrospective study of 17 consecutive patients with recurrent tumors of ameloblastoma in a Teaching Hospital in Nigeria.

The relevant clinicopathologic information, histology slides, and blocks were retrieved and reviewed. Descriptive analysis was used to determine the frequency, tables for categorical variables, and a Chi-square test was used to determine the statistical significance.

Recurrent tumors constituted 33.3% (17/51) of all confirmed diagnoses of ameloblastoma. The diagnostic outcome of the recurrent tumors was conventional ameloblastoma 58.8% (10), unicystic ameloblastoma 5.9% (1), and ameloblastic carcinoma 35.3% (6). There was bilateral mandibular extension in 60.0% (9), pain 58.8% (10), ulceration 29.4% (5), and matted lymph nodes 5.9% (1). Tumors with positive fluid aspirates 82.4% (14) yielded dark-brown fluids in 90.0% (9) of recurrent ameloblastomas and in 66.7% (2) of ameloblastic carcinomas. Atypical peripheral hyperplasia, nuclear hyperchromatism, and increased vascularization were commonly observed in benign recurrences. The frequency of recurrence is significantly associated with the biological behavior of ameloblastoma P = 0.03.

Recurrent tumors of ameloblastoma presented atypical features and malignant transformation.