Very large Ameloblastic Fibroma with Calcifying Odontogenic Cyst in an 8-year-old child. Histological and immunohistochemical characterisation.

Background: Ameloblastic fibroma (AF) is an uncommon odontogenic tumour that may present an aggressive behaviour and may have potential for malignant transformation. Ghost cell (GC) differentiation within AF is extremely rare. There are only seven cases in the international literature in which ghost cells are found in AF.

Case Report: In this study, we report a case of a 8-year-old female child with a cystic-solid mass, measuring 3 x 1.7 x 1.2 cm, characterised by mixed odontogenic tumour, with AF in most of the lesion, with areas characterised by GC, while ameloblastic and ameloblastic fibrodontoma areas were also detected. Other histological sections showed only AF tissue, with areas of Calcifying Odontogenic Cyst. The immunohistochemical characterisation of the lesion was also performed. A comparative table of the immunoistochemical staining of the AF and COC areas revealed some differences in the expression of markers.