Introduction: Unilateral tonsillar enlargement is often seen in the out-patient setting. Frequently, these patients are listed for tonsillectomy for the purpose of ruling out malignant histology. This study aims to determine the necessity for tonsillectomy.

Method: This retrospective case-note review looks at all the tonsillectomies performed for histological examination at our institution over a five year period, and analyses the histological findings in those with unilateral tonsillar enlargement (UTE) alone, and those with UTE with other clinical features (history of chronic pain, dysphagia, the presence of tonsillar or peritonsillar mucosal abnormality, those with cervical lymphadenopathy). All patients who underwent tonsillectomy for the purpose of histological examination from 1 June 1998 to 30 May 2003 were identified and their notes reviewed. Exclusion criteria included cases where there were no pre-operative out-patient notes, those patients where the specimens had been sent from other hospitals, those patients who had malignancy already diagnosed, and those cases where tonsillectomy had been performed by other surgical specialties (e.g. maxillofacial, plastics). There were 1475 tonsillectomies, of which 181 performed over this period were sent for histological analysis. After excluding those patients that did not meet our criteria, we were left with 53 patients who had UTE. The primary outcome measure was the rate of malignancy in the two groups.

Results: Of these, 33 had UTE alone, 20 had associated clinical features. In the former group, none of the patients were found to have malignancy. In the latter, nine (45 per cent) had a malignancy. Fisher's exact test was used to test for differences between the UTE alone group versus the UTE plus other features group (p<0.001).

Discussion: The prevalence of malignancy in tonsils which exhibit asymmetry with no other clinical features is very low; in our study it was zero. However, other studies have found a small percentage representing underlying malignancy. In view of this, we feel that a ‘watch and wait’ policy is initially more appropriate, and if symptoms or signs are progressive, tonsillectomy should then be advised.