Fine Needle Aspiration Cytology of Acanthomatous Ameloblastic Carcinoma – Camouflaging as a Parotid Tumor

Abstract

Background: Ameloblastoma is a rare odontogenic tumor of jaw accounting for 1% of all cysts and tumors of the jaws, more so the acanthomatous variant. Although histopathology and imaging findings of this tumor have been well documented, fine-needle aspiration cytology (FNAC) reports are rare. Cytology becomes more challenging when it camouflages as a parotid tumor. Objectives: The aim of this study was to highlight FNAC as an effective diagnostic tool in the presumptive diagnosis of acanthomatous ameloblastic carcinoma. Materials and Methods: A 28-year-old male, a schizophrenic, presented with parotid region swelling, clinically suspicious of pleomorphic adenoma. General systemic examination and other relevant investigations did not reveal any significant finding. Computed tomography showed a multilocular radiolucent lesion involving left angle and ramus of the mandible suggestive of a neoplastic etiology. FNAC smears showed microbiopsies, cohesive sheets, pseudopapillary pattern, and solid nests of basaloid cells with peripheral palisading along with many multinucleated giant cells and keratinous material. The basaloid cells had bland chromatin, scanty cytoplasm. At places, squamoid cells were seen adjacent to the basaloid cell clusters. Spindle-shaped cells in small clusters, monocytoid cells, and normal clusters of salivary gland acini were also noted. A diagnosis of acathomatous ameloblastoma was rendered which was confirmed on histopathology as acathomatous ameloblastic carcinoma. Conclusion: Ameloblastoma should be considered in the differential diagnosis of basaloid cell-rich lesions occurring in parotid region. Awareness of distinct cytomorphologic features of acanthomatous ameloblastoma helps in accurate diagnosis and in choice of surgery, thereby reducing recurrence rate.

Keywords

• acanthomatous
• ameloblastoma
• cytology
• fine-needle aspiration cytology.