Zymogen-poor acinic cell carcinoma of the soft palate with high-grade transformation.

Acinic cell carcinoma is an uncommon malignant salivary gland tumour accounting for approximately 6-7% of all salivary gland neoplasms. The key diagnostic feature of acinic cell carcinoma is the presence of acinar cell differentiation characterised by cytoplasmic zymogen secretory granules. This tumour shows a variety of growth patterns, including solid, microcystic, follicular and papillary cystic patterns. Acinic cell carcinoma is typically a cytologically low-grade malignancy. Acinic cell carcinomas with high-grade transformation (HGT) are exceedingly rare and are reported to have a more aggressive clinical course than conventional acinic cell carcinoma. This is a case report of this uncommon entity with high-grade transformation arising on the soft palate in a 64-year-old woman.