The Extraosseous or Peripheral Ameloblastoma (PA) is a rare and benign odontogenic tumour, representing 1% to 5% of all ameloblastomas. It is usually localized in the soft oral tissues, without deep bone involvement. Its biological behaviour is specific, and several authors define PA as a non-infiltrating hamartomatous lesion. Indeed, recurrences rarely occur and progression in malignant tumors appears to be rare.

The PA originates from the tooth-forming apparatus and it consists of proliferating odontogenic epithelium, exhibiting the same histological cell types and patterns of the intraosseous counterpart or infiltrating ameloblastoma.

The peripheral desmoplastic ameloblastoma (PDA) can be classified as a newly recognized and very rare histological variant. To our knowledge, only a few cases of adult patients affected by PDA have been published.

The aim of this paper is to report a case of PDA affecting an adolescent patient. The clinical-pathological and immunohistological features are discussed in order to improve knowledge regarding a correct diagnosis and to differentiate PDA lesions from similar diseases.