There is continued controversy over the extent of parotidectomy required for removal of a benign pleomorphic adenoma from the parotid gland. Currently, consensus exists that the integrity of the facial nerve must be preserved when the tumour is totally removed.

As a result of experience gained in the first half of the twentieth century, it was recommended that superficial parotidectomy with facial nerve dissection should be the minimal biopsy for pleomorphic adenoma. Since that time, however, research has indicated that partial parotidectomy or extracapsular dissection of benign pleomorphic adenoma can be accomplished with preservation of the facial nerve without an increase in tumour recurrence. Partial parotidectomy or extracapsular dissection results in impaired cosmetic results and a lower incidence of Frey's syndrome, and thus may be the preferred approach when undertaken by experienced surgeons.

Salivary gland myoepitheliomas are rare tumours, accounting for less than 1 per cent of neoplasms of the salivary glands. Myoepithelioma of the palate is very rare, and only a few cases have been reported in the world literature. Histological and immunohistochemical analysis supports the myoepithelial origin of this tumour. Here, we report three cases of myoepithelioma of the palate in adult males and review previously reported cases.

Two cases of deep lobe parotid tumours extending into the parapharyngeal space and causing obstructive sleep apnoea are described. Post-operatively, marked improvements in nocturnal hypoxic episodes and the symptoms of obstructive sleep apnoea were seen. Although minor salivary gland pleomorphic adenomas have been described as a cause of airway compromise, pleomorphic adenomata arising from the deep lobe of the parotid, causing proven obstructive sleep apnoea, have not previously been documented. The anatomy and common pathologies of the parapharyngeal space are discussed.

A case of an isolated pleomorphic adenoma of the retropharyngeal space is reported, this has not been documented previously in the literature. Attention is drawn to the wide spectrum of benign and malignant neoplasms that can potentially occur within this complex anatomical region. The importance of a systematic and logical approach to the management of such lesions is emphasized.

Recurrent pleomorphic adenoma of the parotid usually occurs in the distribution of the primary procedure. There are numerous reports of widespread local recurrence and a few reported cases of distant metastases. Extensive seeding throughout the entire ipsilateral neck is rare. Treatment involves a combination of radical surgery and radiotherapy. The potential for malignant transformation demands close follow-up of younger patients particularly.

A case of carcinoma ex pleomorphic adenoma arising in the soft palate is reported. The tumour presented had enlarged gradually over 10 years and finally occupied the oral cavity. The patient was admitted to our hospital due to disturbance of her speech and swallowing, and a sudden haemorrhage from the tumour. The initial pathological diagnosis by open biopsy was benign pleomorphic adenoma. After total resection, histological examination revealed that the tumour was composed partly of benign pleomorphic adenoma and partly of an adenocarcinomatous component. The carcinoma cells with prominent nucleoli were spheroid or polygonal in shape, and frequently formed ductal structures with areas of necrosis. Mitoses were also found. These findings showed that this tumour was a secondary carcinoma which had developed in a preexisting pleomorphic adenoma.

Carcinosarcoma of the salivary glands are rare tumours, often associated with a history of pleomorphic adenoma. A case of carcinosarcoma of the parotid arising following irradiation to the resection site of a pleomorphic adenoma is presented. The clinical and histological features are discussed and the literature reviewed.

Of 209 cases of pleomorphic adenoma treated in a 30 year period, 38 were secondary referrals with recurrent disease following surgery. Of these, 25 were women and 13 men with a mean time to recurrence of 9 years 4 months. Thirty-four recurrences were in the parotid gland. three in the submandibular gland and one in the anterior faucial pillar.

Seven patients were untreated due to poor general condition or refusal of further treatment. Of the remainder, 15 had superficial parotidectomy and excision of the scar and nine a total parotidectonly. Three of these had extensive surgery with local flap repair. Of the patients with submandibular gland recurrence, two had local excision and one was treated with radiotherapy alone. One patient had a recurrence in the laucial pillar. Three patients developed malignant change in the recurrent tumour. of whom one died of disease.

Immunohistochemical study of major salivary gland tumours was performed on 60 pleomorphic adenomas, five basal cell adenomas and 10 adenoid cystic carcinomas to determine the diagnostic value of each antigen. Immunoreactivity examined were intermediate filaments (keratin, vimentin, desmin and glial fibrillary acidic protein [GFAP]) and related substances (actin, S-100 protein and secretory component). In pleomorphic adenomas, there was positive immunoreactivity for GFAP which was not observed in normal tissue or other neoplastic tissues. Immunoreactivity of GFAP was closely related to myxomatous and early chondromatous differentiation in pleomorphic adenoma. It is considered that GFAP immunoreactivity should be assessed in the occasional differential diagnostic dilemma of pleomorphic adenoma versus adenoid cystic carcinoma and basal cell adenoma, because of its ability to show potential and definite myxochondromatous differentiation.