Bone Formation in Pleomorphic Adenoma: A Case Report

Pleomorphic adenoma is a benign tumour with variable cytomorphological and architectural elements. It is the most common salivary gland tumour in children and adults. We report a case of a 32-year-old Malay woman who presented with a slow-growing, painless, firm, and mobile nodule of 1 cm x 1 cm in size at the angle of her mandible on the right side which could be palpated bimanually. Intraorally, this nodule could be palpated at the retromolar area. On excisional biopsy, this nodule was reported as a pleomorphic adenoma with predominant chondroid stromal elements and a large area of bone formation in the stroma. We discuss the possible pathogenesis, differential diagnosis, and clinical significance of this exceptionally rare phenomenon of bone formation in pleomorphic adenoma in minor salivary glands with the literature review. The clinical significance and relevance on treatment outcome for pleomorphic adenoma with bone formation is currently uncertain as there are only a few cases reported in the literature. A good follow-up study is recommended to assess the clinical significance of pleomorphic adenoma with extensive bone formation.