Peripheral Desmoplastic Ameloblastoma: Report of an Extremely Rare Presentation and a Literature Review

Case Report

Austin J Surg. 2018; 5(3): 1132.

Peripheral Desmoplastic Ameloblastoma: Report of an Extremely Rare Presentation and a Literature Review

Ramphul A¹*, Kho Y² and Mehanna P¹

¹Oral and Maxillofacial Surgery Registrar, Division of Surgery, John Hunter Hospital, Australia

²Resident Medical Officer, Prince of Wales Hospital, Australia

*Corresponding author: Ramphul A, Oral and Maxillofacial Surgery Registrar, Division of Surgery, John Hunter Hospital, Newcastle, Australia

Received: January 09, 2018; Accepted: February 12, 2018; Published: February 22, 2018


Thedesmoplastic variant of Peripheral Ameloblastomais an extremely rareform of Ameloblastoma. There are only five reported cases of Peripheral Desmoplastic Ameloblastoma (PDA) in the English literature. Peripheral Desmoplastic Ameloblastomapresents as a soft tissue mass on the tooth bearing areas of the jaw and has very distinct histological features, characterised by de novo synthesis of collagen. In general, Peripheral (extra osseous) forms of Ameloblastomaare considered to be less aggressive their Central (intra osseous) variant, with significant difference in their management. However, the paucity of information on the much rarer desmoplastic subtypes of Peripheral Ameloblastoma makes it impossible to assess its biologic behaviour. Clinical vigilance is hence warranted with this form of Ameloblastoma. We reviewed the literature and present the case of a 60-year-old male presenting with a PDA on the mandibular attached gingival in the right first premolar area.


Ameloblastoma is a slow growing tumour of the jaw. It is a tumour of odontogenic origin and accounts for 1% of all oral tumours and about 18% of odontogenic tumours [1]. It can present either as an intra osseous or an extra osseous lesion. The extra osseous form arises from the gingival or alveolar mucosa and is known as Peripheral Ameloblastoma (PA).

The follicular and plexiform variants are the most common histological subtypes of ameloblastoma. Less common histological variants include the acanthomatous, granular, basal cell, keratoameloblastoma and clear cell subtypes [2]. The desmoplastic subtype of Ameloblastoma is very rare. There does not appear to be a relationship between the histology of the more common histological variants and prognosis [3]. On the other hand, it is hard to predict the biological behaviour of the desmoplastic variant due to the paucity of information in the literature.

Peripheral Ameloblastoma is a soft tissue tumour occurring on the tooth bearing areas of the maxilla or mandible [4] and most commonly manifests as a slow growing, firm, painless mass with a sessile or pedunculated base. It usually has a smooth texture but can sometimes be pebbly, granular, papillary or warty [4,5] with a colour that can vary from that of normal mucosa to pink, red or dark red [5,6]. The lesion can also demonstrate an ulcerated or a keratotic appearance (frictional keratosis) due to trauma during mastication [4]. The mandibular premolar area is the most common site of presentation, accounting for 32.6% of all sites [4]. It is common for PA to erode cortical bone by mass effect. This is referred to as cupping or saucerisation.

The desmoplastic variant of Peripheral Ameloblastoma is an extremely rare form of Ameloblastoma and presents with very distinct histological features, with only 3 reported cases that we have been able to identify in the literature.

The authors describe a case of a PDA in the mandibular premolar area in a 60 year old and review the literature on the subject.

Case Presentation

A 60-year-old man presented with a few weeks history of a hard gingival swelling on the buccal gingival of his first right mandibular premolar (44). A well-circumscribed firm lesion around 7 mm in diameter was noted in the right canine/first premolar area, with no pain or mobility of any of the adjacent teeth (Figure 1). The lesion was non-tender with no gingival erythematic, ulceration or bleeding noted or reported. Cone Beam CT showed an expansive radiolucent lesion in the premolar/canine area (Figure 2). Following discussions with the patient, he underwent an excision biopsy of the lesion. The biopsy specimen showed squamous mucosa and sub mucosa with small bone trabeculae present on the deep surface (Figures 3,4). In the sub mucosa there was a circumscribed neoplasm consisting of nests of cells in a fibrotic stroma with the nest having a peripheral layer of palisade small cuboidal cells with a high Nuclear: Cytoplasmic ratio, oval, even nuclei and scanty neoplasm. The central cells were squamoid with some squamous nests. There was no necrosis, mitosis nor were pleomorphism and the histological findings consistent with the diagnosis of Peripheral Desmoplastic Ameloblastoma (PDA). The peripheral margins of the specimen were clear but the deep margin was positive. The patient had surgery again where the deep margin was mechanically derided with a round bur by 2-3 mm. This time, the histopathology analysis reported a clear margin. The patient has now been followed up for three years and there is no evidence of recurrence.