Adenomas of the parotid gland. Management and reevaluation of Warthin tumors

During a ten year period 344 patients with benign parotid tumors from both southern and northern Sweden were operated on and histologically classified by 12 different pathologists who followed the WHO classification from 1972. Pleomorphic adenoma was diagnosed in 283 patients, adenolymphoma in 49 and 12 patients were classified as subgroups of other adenomas. interestingly, the frequency of benign tumors other than pleomorphic adenomas Varied with 23 percent in the southern region compared to 13 percent in the northern area. The morphological criteria for these lesions are unchanged in the second edition(1991) of the WHO classification of salivary gland tumors. However, the earlier group of monomorphic adenomas was separated for identification and categorized. in this study histological reevaluation of the non-pleomorphic group by one pathologist revealed apart from terminology, consistent diagnoses regarding the frequency of Warthin (adenolymphoma) tumors. This re-evaluation of the benign parotid tumors other than pleomorphic adenomas disclosed that the histo-pathological diagnosis is usually easy. Their Varying geographical occurrence is notable and is further discussed below.