Warthin tumor with acinic cell carcinoma of the parotid gland

Objective To report a case of Warthin tumor complicated with acinic cell carcinoma in the parotid gland and to investigate their histogenesis. Methods Clinicopathologic features and immunohistochemistry of CK7,CK19, 34βE12 and Ki-67 were observed with review of the literatures. Results Two tumors were presented in the parotid gland of the same side. One was situated in the deep portion with 2^7cm in its greatest dimension. The histology showed a typical Warthin tumor. In the shallow portion of the same parotid gland, a nodule of 0^8cm in greatest dimension was noted. The histology revealed an acinic cell carcinoma. Both tumors expressed CK7, CK19, 34βE12, similar to those in the normal terminal ducts and intercaiated cells. Conclusions Collision tumor of Warthin tumor and acinic cell carcinoma in the same parotid gland is extremely rare. The immunohistochemical findings support the histogenesis of terminat ducts or multipotential cells.