Peripheral Ameloblastoma with Dystrophic Calcification: An Unusual Feature in Non-Calcifying Odontogenic Tumors

Peripheral ameloblastoma is a rare extraosseous counterpart of central ameloblastoma that occurs in soft tissues and may cause bone crest resorption. This study reports a peripheral ameloblastoma on the buccal gingiva of a 56-year-old man, which presented extensive squamous metaplasia areas, keratinization and dystrophic calcifications in the neoplastic islands. It is emphasized the need of a detailed imaging study and a long follow-up period to exclude bone involvement whenever peripheral ameloblastoma diagnosis is considered.

Ameloblastoma periférico é a contraparte rara extraóssea do ameloblastoma central, que ocorre em tecidos moles e pode causar reabsorção da crista óssea. Este estudo reporta um ameloblastoma periférico localizado na gengiva vestibular de um homem de 56 anos de idade, que apresentava extensas áreas de metaplasia escamosa, queratinização e calcificação distrófica dentro das ilhas neoplásicas. É enfatizada a necessidade de um estudo de imagem detalhado e acompanhamento prolongado para excluir envolvimento ósseo sempre que o diagnóstico de ameloblastoma periférico for considerado.

Different Protein Expressions between Peripheral Ameloblastoma and Oral Basal Cell Carcinoma Occurred at the Same Mandibular Molar Area

Peripheral ameloblastoma (PA) in gingiva is rare and often confused with oral basal cell carcinoma (OBCC). The tissues of one case of PA and one case of OBCC with the same mandibular molar area affected were compared via an immunohistochemical examination using 50 antisera. The PA and OBCC showed similar proliferation of basaloid epithelial strands, but toluidine blue staining revealed that the PA had pinkish juxta-epithelial myxoid tissue, whereas the OBCC was infiltrated by many mast cells. Immunohistochemical comparisons showed that the PA was strongly positive for ameloblastin, KL1, p63, carcinoembryonic antigen, focal adhesion kinase, and cathepsin K, and slightly positive for amelogenin, Krox-25, E-cadherin, and PTCH1, whereas the OBCC was not. On the other hand, the OBCC was strongly positive for EpCam, matrix metalloprotease (MMP)-1, alpha1-antitrypsin, cytokeratin-7, p53, survivin, pAKT1, transforming growth factor-beta1, NRAS, TGase-1, and tumor nescrosis factor-alpha, and consistently positive for beta-catenin, MMP-2, cathepsin G, TGase-2, SOS-1, sonic hedgehog, and the beta-defensins-1, -2, -3, while the PA was not. These data suggest that the tumorigeneses of PA and OBCC differ, and that PAs undergo odontogenic differentiation and generate oncogenic signals for infiltrative growth and bone resorption, whereas OBCCs undergo basaloid epidermal differentiation as a result of growth factor/cytokine-related oncogenic signals.

Peripheral Ameloblastoma - A Case Report With Emphasis On Etiopathogenesis.

Peripheral ameloblastoma, a rare and unusual variant of odontogenic tumour, comprises about 1% of all ameloblastomas. The extraosseous location is the peculiar feature of this type of tumour, which is otherwise similar to the classical ameloblastoma. It appears in the gingiva and oral mucosa and it usually does not show any bone involvement on radiographs, except for saucer shaped erosion of underlying alveolar bone. Recurrence is considered uncommon. We report a case of peripheral ameloblastoma of maxillary gingiva.

Central plexiform ameeloblastoma with exophytic growth a rare case report with review of literature.

Ameloblastomas are predominantly benign, intra-osseous odontogenic tumors and mucosal involvement is a rare secondary phenomenon, occurring only after a long period of intra-osseous growth and bone expansion. This article presents a case report of an eleven year old male patient with a large plexiform ameloblastoma which invaded the soft tissues, presented as an exophytic growth in the mandibular anterior region with radiographic feature of a large unilocular radiolucenc y and displaced mandibular left central incisor. The management comprised of surgical removal of ameloblastoma under local anesthesia along with extraction of displaced mandibular left central incisor.

Peripheral ameloblastoma: A case report / 대한구강악안면방사선학회지

Peripheral ameloblastoma is an extremely rare odontogenic soft tissue tumor with histologic characteristics similar to those of the intraosseous ameloblastoma. It appears in the gingiva and oral mucosa. And it usually does not show any bone involvement on radiographs, except for saucer shaped erosion of underlying alveolar bone. Recurrence is considered uncommon. We report a case of peripheral ameloblastoma with bone involvement. Histologically it presented with follicles and nest of tumor cells with palisading pattern. And radiographs showed the typical saucer shaped alveolar bone erosion at the distal area of right mandibular third molar. At 6-month follow-up after operation, no local recurrence was noted.