Clinicopathologic study of pleomorphic adenoma in minor salivary glands

ABSTRACT

Pleomorphic adenoma is the most common salivary neoplasm mainly occurring in the major salivary glands - especially in parotid gland, which is characterized by variable histopathologic appearances and high recurrence rate with malignant transformation according to surgical situations. And this benign mixed tumor occurring in minor salivary glands is believed to shows same clinicopathologic appearances and relatively low recurrent rate compared with the case in major salivary glands. But there are few comparative studies of large series of pleomorphic adenoma occurring in minor salivary glands which includes different histopathologic appearance, clinical characteristics, treatment methods, recurrence rate, and malignant transformation. We retrospectively studied the 54 patients who were pathologically confirmed with pleomorphic adenoma occurring in minor salivary glands, and analyzed the clinico-histopathological appearance, surgical methods, recurrent cases. The results obtained are as follows. 1. The incidence of the tumor was most frequent in 4th & 5th decade, and in female. 2. Palate(90%) including hard & soft palate was the most frequent site for pleomorphic adenoma in minor salivary glands. 3. The exact duration could not be known due to asymptomatic slow growth patterns of the tumor. 4. The mean tumor size was 2.3cm. 5. 28 (52%) pleomorphic adenomas were classified as Cellular type (cell-rich), 17 (31%) specimen as Intermediate type(equal cell to stroma ratio), and 9 (17%) as Myxoid type(stroma-rich). 6. Surgically 51 cases (94%) were showed well-encapsulated tumors, but histopathologically only 34 specimen (63%) were wellencapsulated. Therefore pleomorphic adenomas in minor salivary glands also have to be excised more widely, not enucleated. And in case of suspicious malignancy or large tumor, preoperative incisional biopsy can be applied in the center of the tumor for prevention of rupture of tumor cell, and total excision with use of frozen biopsy for detection of malignancy and confirming the excision m argin, and closed follow-up according to final histopathologic results is recommended.