Bilateral carcinoma in situ of Wharton's duct after chronic obstructive sialadenitis: inflammation as the cause of malignancy?

A case of bilateral carcinoma in situ of Wharton's duct after chronic sialadenitis is reported. The patient, a 54-year-old man, complained of recurrent pain and swelling in the left lower submandibular region. Computed tomography showed large stones in the hilar area of both submandibular glands. The patient underwent bilateral submandibular excision. Histologic and immunohistochemical examination revealed squamous metaplasia with areas of carcinoma in situ in both right and left ducts adjacent to the calculus. To the best of our knowledge, this is the first case report in the literature describing an association between obstructive sialadenitis and carcinoma in situ of Wharton's duct. We discuss etiologic factors and chronic inflammation as a possible cause of malignancy.