Polymorphous low-grade adenocarcinoma (PLGA) is an uncommon malignant tumor of the salivary glands. Histologically, PLGA may have overlapping features with adenoid cystic carcinoma (ACC), posing difficulty in differentiating one from the other. We, here, presented a case of PLGA and a comparative immunohistochemical study with ACC by the use of a panel of antibodies. The patient was a 52-year-old Thai female who had a painless mass on the right side of the palate. An incisional biopsy revealed characteristic histopathologic features of PLGA. A partial maxillectomy was performed without any complication. On a two-year follow-up, the patient remained healthy and had no evidence of recurrence of the tumor. The results of the comparative immunohistochemical profiles between PLGA and ACC revealed no clear differences between these two rumors. Further studies with different markers may prove to be beneficial in differentiating between PLGA and ACC.Polymorphous low-grade adenocarcinoma (PLGA) is an uncommon malignant tumor of the salivary glands. Histologically, PLGA may have overlapping features with adenoid cystic carcinoma (ACC), posing difficulty in differentiating one from the other. We, here, presented a case of PLGA and a comparative immunohistochemical study with ACC by the use of a panel of antibodies. The patient was a 52-year-old Thai female who had a painless mass on the right side of the palate. An incisional biopsy revealed characteristic histopathologic features of PLGA. A partial maxillectomy was performed without any complication. On a two-year follow-up, the patient remained healthy and had no evidence of recurrence of the tumor. The results of the comparative immunohistochemical profiles between PLGA and ACC revealed no clear differences between these two rumors. Further studies with different markers may prove to be beneficial in differentiating between PLGA and ACC.