Abstract
Polymorphous low-grade adenocarcinoma (PLGA) is a malignant tumor of minor salivary glands, most frequently seen on the palate. It is characterized by cytologic uniformity and histologic blandness, with variable, infiltrating growth patterns. The authors report here three caces of PLGA. The tumors were found on the right inferior surface of the tongue in case 1, and on the palate in cases 2 and 3. In case 1, partial glossectomy with supraomohyoid neck dissection was performed, because of submandibular lymphnode metastasis, and partial resection of the palate was done in cases 2 and 3. In cases 1 and 2, neither recurrence nor metastasis was recognized in follow-up observation of from 4 to 7 years. Case 3 died of old age 8 months after surgery. The histopathologic findings of the excised tumors showed various growth patterns, i.e. solid, tubular, cribrif orm, trabecular, and lobular, although tumor cells were small or medium in size, with a uniform round nucleus, and mitosis was rare. By immunohistochemical examinations, a part of tumor cells in case 1 was positive for cytokeratin and S-100 protein, while tumor cells of cases 2 and 3 were positive for not only cytokeratin and S-100 protein but also vimentin and actin. Expression of carcinoembryonic antigen and epitherial membrane antigen was not observed in the three cases.
