Adenoid ameloblastoma with dentinoid and cellular atypia: a rare case report

Adenomatoid odontogenic tumor (AOT) is always a benign tumor with rare incidence of recurrence while ameloblastoma is the commonest gnathic tumor, which is always aggressive. Although co-occurrence of these lesions has been reported, this paper describes a homogenous combination of atypical AOT and ameloblastomatous proliferation with some malignant microscopic features. To date, a dozen cases or slightly more of this uncommon composite odontogenic tumor have been, quite correctly, reported in the literature under the designation of adenoid ameloblastoma. Of these, neither cellular atypia nor pleomorphism has been revealed. This extremely rare ameloblastomatous variant can pose a significant diagnostic challenge. Moreover, we report new findings of severe nuclear vacuolization, mitotic figures, cellular pleomorphism and nuclear hyperchromatism and chromatin peripheralization. However, the scattered occurrence of these was not sufficient for claiming a malignancy. To confirm, two immunohistochemical markers - calretinin and p53 - were recruited. Rendering itself to be suspicious, a rapt attention should be paid toward well interrogating this lesion histologically and immunohistochemically.