A case of polymorphous adenocarcinoma of the upper lip

Abstract

Polymorphous adenocarcinoma （PAC） is a rare malignant salivary gland tumor arising most commonly in the palate. It is characterized by cytologic uniformity but morphologically variable growth pattern. We report a case of PAC arising in the upper lip. A 69-year-old man was referred to our hospital due to a tumor in the right side of the buccal mucosa. Clinical examination showed a 9×9 mm painless and well-demarcated swelling of the buccal mucosa without mucosal ulceration. MRI revealed a well-defined mass in the right side of the buccal mucosa, of moderate intensity on T1 weighted images and high intensity on T2 weighted images. The tumor was surgically removed under general anesthesia. Histological examination of the surgical specimen showed PAC. After the diagnosis of PAC, an additional surgical excision with a 5-mm wide margin from the scar after the operation was performed as a second surgery. There has been no sign of recurrence or metastasis for 4 years postoperatively.