[Well-differentiated acinic cell carcinoma of the parotid]

Well-differentiated acinic-cell carcinoma of parotid gland. The authors report a case of well-differentiated acinic-cell carcinoma of the parotid gland with an important lymphoid component, whereas in the aspiration a diagnosis of adenolymphoma was made. In our case cytologic examination showed an abundant cellularity, consisting mostly of lymphocytes. Epithelial elements were monomorphic and had a discrete quantity of amphophilic, granular cytoplasm. Such structures sometimes appeared to be in continuity with ductal-type formations, suggesting normal glandular acini of the serous type. Elements oncocytes-like with abundant, basophilic granular cytoplasm were seen also. These cells oncocytes-like, the rich lymphoid component and the presence of little amorphous debris, suggested an adenolymphoma. The differential diagnosis between ACC, adenocarcinoma, and lymphonodal metastasis did not show problems because of the lacking of the cytological atipie. Histologic examination of the surgical specimen did not show problems of differential diagnosis. Morphologic patterns included acinar, tubuloductal, microcystic and follicular structures. Periodic acid Schiff positivity, resistant to diastase, was noted in most serous cells. An acid alcian blue stain was negative within the cell cytoplasm but moderately positive in the microcystic cavities. The final histologic diagnosis was that of a well-differentiated acinic cell carcinoma with a rich lymphoid component.