Metachronous Bilateral Acinic Cell Carcinoma of the Parotid Gland in a Young Woman.

Bilateral involvement of major salivary glands by carcinoma of an identical histologic subtype is uncommon. In this study, a 26-year old female patient was diagnosed to have a low-grade acinic cell carcinoma (ACC) in the left parotid gland. After superficial parotidectomy, she was referred to the oncological dispensary care without further oncological therapeutic intervention. During 11 years of follow-up, she had no evidence of locoregional recurrence or metastasis. However, at the age of 37, she was recognized to have another tumor mass in the contralateral parotid gland. Right superficial parotidectomy was done, and histology confirmed an ACC showing the same picture as it was found previously. A year after the operation, no sign of tumor relapse was seen. Although metachronous bilateral ACC of the parotid gland is very rare, it is occasionally encountered in medical practice. Such an event may occur many years after a diagnosis of the initial tumor. Every patient once treated for parotid ACC warrants periodical clinical examinations and long-term follow-up (more than 10 years), even with attention to the contralateral non-affected parotid gland.