Adenoid cystic carcinoma arising in association with pleomorphic adenoma in a background of chronic sclerosing sialadenitis (Küttner tumor)

Abstract

Chronic sclerosing sialadenitis of the salivary gland is associated with IgG4 containing plasma cell infiltrate and fibrosis. Other manifestations of IgG4 disease may be present while salivary gland neoplasms are rarely seen. Here we describe the case of a 77-year-old male who presented with chronic right submandibular gland swelling that was diagnosed as pleomorphic adenoma on fine needle aspiration. He underwent right submandibular gland resection, and the pathology showed an adenoid cystic carcinoma with a high proliferative index and perineural invasion arising in association with a pleomorphic adenoma. The background salivary gland was consistent with chronic sclerosing sialadenitis. Clinical follow-up revealed markedly elevated serum IgG4 levels and radiologic findings consistent with diffuse autoimmune pancreatitis. While the association between neoplasms and IgG4-related salivary gland disease is unclear, this case emphasizes the importance of ruling out malignancy and thoroughly evaluating for systemic IgG4-related disease in the setting of chronic sclerosing sialadenitis.