CLINICAL-SIGNIFICANCE OF THE TUMOR CAPSULE IN THE TREATMENT OF PAROTID PLEOMORPHIC ADENOMAS

The propensity of pleomorphic adenomas to recur is generally attribute d to the biological nature of the tumour, and surgery close to the cap sule is perceived as undesirable. At the Christie Hospital, Manchester , between 1947 and 1992, 475 tumours arising within the superficial po rtion of the parotid gland were treated by two surgical techniques: ex tracapsular dissection (380 patients) and superficial parotidectomy (9 5). Recurrence rates were 2 per cent in each group (median follow-up 1 2.5 years). Contact of the tumour with the facial nerve was recorded i n 51 per cent of patients. There was no difference between the treatme nt groups in the incidence of permanent facial nerve injury (2 versus 1 per cent respectively). This study demonstrates that dissection in c lose proximity to the tumour is possible without inducing recurrence a nd that in practice the microinvasion of the capsule by tumour buds ha s limited clinical significance.