title: Spindle cell variant of ameloblastic carcinoma arising from an unicystic amelobastoma: Report of a rare case.
abstract: Malignant transformation of ameloblastomas arising from an odontogenic cyst or de novo is well-recognized. Malignancies in ameloblastomas may involve metastasis or a local dysplastic change in the tissue. The latter are classified as ameloblastic carcinomas. A 75-year-old male presented with a mandibular cystic swelling, with no evidence of metastasis. Dysplastic ameloblastic cells with spindle-cell transformation were seen arising from a cystic lining with features of a unicystic ameloblastoma. Immunohistochemically the lesion stained positive with cytokeratin 8,19 and alpha smooth muscle actin, but was negative for vimentin. A diagnosis of spindle-cell ameloblastic carcinoma was made. Spindle-cell ameloblastic carcinomas are rare and this is the second case arising from a unicystic ameloblastoma reported in literature. The recognition of this transformation and inclusion of this entity in the classification of ameloblastic carcinomas is stressed.
authors.affiliation: Department of Oral and Maxillofacial Pathology, Dr. Syamala Reddy Dental College, Hospital and Research Center, Munnekolala, Marathalli, Bangalore, India.
authors.forename: Venkatesh V
authors.initials: VV
authors.lastname: Kamath
authors.forename: Krishnanand
authors.initials: K
authors.lastname: Satelur
authors.forename: Komali
authors.initials: K
authors.lastname: Yerlagudda
keywords: Ameloblastic carcinoma; ameloblastoma; odontogenic carcinoma; spindle-cell transformation; unicystic ameloblastoma