Objective The purpose of this studywas to offer pathological reasons for partial parotidectomy adopted in pa- rotid pleomorphic adenoma treatment.Methods Continuous slices from 25 cases of primary parotid pleomorphic adenoma were carefully examined and the extra-envelope infiltration, the budding and the primary multi-centerwere measured and recorded.Re- sults The range of extra-envelope infiltration and buddingwas limited in 0·09~0·285 mm out of tumor capsules, whichwas far less than the safe boundary(1 cm)of the partial parotidectomy. Two cases with multi-centers were found, but all the centers were aggregated together and encapsulated in a united envelope.Conclusion Partial parotid parotidectomy is a safe method and can remove the tumor completely in parotid plemorphic adenoma treatment.
