Multiple pleomorphic adenomas arising in the parotid and submandibular lymph nodes.

We report rare case of multiple pleomorphic adenomas arising in the parotid and submandibular lymph nodes of a 21-year-old man. These tumours were surrounded by lymphoid tissue which was almost identical to that of the cortex of lymph node. The possibility of metastasizing pleomorphic adenomas was discounted because the mitotic activity was low and there were no signs of infiltration. Heterotopic salivary gland tissue was also found in the lymph nodes that contained the tumours, and each tumour expressed a similar immunohistochemical staining pattern to that of the salivary gland tissue. These findings indicate that these pleomorphic adenomas probably arose from the salivary gland tissue within the lymph nodes.