A case of acinic cell carcinoma ex pleomorphic adenoma arising in the parotid gland

Abstract

A case of acinic cell carcinoma ex pleomorphic adenoma arising in the parotid gland is reported. A 32-year-old woman visited our hospital with the chief complaint of a left asymptomatic parotid tumor 30 mm in diameter. Subsequently, she underwent an extended total parotidectomy because of the involvement of a branch of the facial nerve and the frozen sections that revealed the tumor, which was diagnosed as malignant. Postoperatively, a series of 50 Gy irradiation doses was performed. Eighty-seven months have passed after the treatment and she has not shown any sign of recurrence.
Carcinoma ex pleomorphic adenoma (CXPA) is an uncommon neoplasm and one of the salivary gland tumors initially assigned to the WHO Classification established in 2005. It arises most frequently in the parotid gland and the occurrence rate in all parotid cancer cases is reported to be 13%. The malignant components of CXPA are mostly reported to be adenocarcinoma NOS, salivary duct carcinoma, anaplastic carcinoma and myoepithelial carcinoma. But based on a thorough search of the literature, we found only one case reported of acinic cell carcinoma ex pleomorphic adenoma. Clinical malignancy of CXPA is defined according to the malignant component of the CXPA. Despite the definition of acinic cell carcinoma as a low grade malignancy, a close follow-up is mandatory.