title: Granular cell ameloblastoma: case report of a particular ameloblastoma histologically resembling oncocytoma.
abstract: Granular cell ameloblastoma is classified as a histological subtype of solid/multicystic ameloblastoma. Usual granular cell ameloblastoma is histologically characterized by granular changes of stellate-like cells located in the inner portion of the epithelial follicles. Here we report a case of another type of granular cell ameloblastoma, showing predominant anastomosing double-stranded trabeculae of granular cells. This type of granular cell ameloblastoma is extremely rare, and the World Health Organization classification does not contain the entity. We tentatively termed it 'anastomosing granular cell ameloblastoma' in this report. The present case suggests the importance of differential diagnosis because the histology of 'anastomosing granular cell ameloblastoma' resembles that of salivary gland oncocytoma rather than that of usual granular cell ameloblastoma. The trabeculae observed in our case continued to the peripheral cells of a small amount of epithelial sheets of plexiform ameloblastoma, and the tumor cells were positive for CK19, which is regarded as an immunohistochemical marker of odontogenic epithelium. Similar to usual granular cell ameloblastoma, the tumor cells had CD68-positive granules. For precise diagnosis of this condition, immunohistochemistry using CK19 and CD68, as well as detailed histological observation, are recommended.
authors.affiliation: Department of Clinical Oral Oncology, Unit of Translational Medicine, Course of Medical and Dental Sciences, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan.
authors.forename: Yuki
authors.initials: Y
authors.lastname: Matsushita
authors.forename: Shuichi
authors.initials: S
authors.lastname: Fujita
authors.forename: Goro
authors.initials: G
authors.lastname: Kawasaki
authors.forename: Yoshinosuke
authors.initials: Y
authors.lastname: Hirota
authors.forename: Satoshi
authors.initials: S
authors.lastname: Rokutanda
authors.forename: Kentaro
authors.initials: K
authors.lastname: Yamashita
authors.forename: Souichi
authors.initials: S
authors.lastname: Yanamoto
authors.forename: Tohru
authors.initials: T
authors.lastname: Ikeda
authors.forename: Masahiro
authors.initials: M
authors.lastname: Umeda
mesh_terms: D018249:Adenoma, Oxyphilic / Q000175:diagnosis; D000564:Ameloblastoma / Q000175:diagnosis*; D003594:Cytoplasmic Granules / Q000473:pathology; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D008339:Mandibular Neoplasms / Q000175:diagnosis*; D008875:Middle Aged; D012468:Salivary Gland Neoplasms / Q000175:diagnosis
keywords: CD68; CK19; granular cell ameloblastoma; oncocytoma