Tumours of the oropharynx

Benign

Benign tumours of the oropharynx are rare, papillomas being the most common. These are usually incidental findings and are rarely of any importance.

Malignant

The most important epithelial tumour is squamous cell carcinoma, which constitutes roughly 90 per cent of all epithelial tumours in the upper aerodigestive tract (Figs 43.30 and 43.31). In the oropharynx the proportion is less (70 per cent) because of the higher incidence of lymphoma (25 per cent) and salivary gland tumours (5 per cent).

Aetiology

Squamous carcinomas of the oropharynx have strong associations with cigarette smoking and the consumption of alcohol, and these two factors cause varying incidence throughout the world. In countries where the consumption of tobacco and alcohol is associated with poor oral hygiene these malignancies assume major importance. Due to the rich lymphatic drainage of the oropharynx, cervical node metastatases are common. They may be the only presenting feature with an apparent occult primary often being unsuspected and missed in the tonsil or tongue base. The majority of lymph node metastases from oropharyngeal squamous carcinomas is to the jugulodigastric node. This is the commonest site for the so-called ‘branchial cyst carcinoma’, but several studies in recent times have shown that this is probably an extremely rare pathology and that usually the diagnosis represents cystic degeneration in a jugulodigastric node from a small undetected primary squamous carcinoma in the tonsil or tongue base. Squamous cell carcinomas are most common in the sixth and seventh decades and more frequent in men.

Treatment

Treatment patterns vary with facilities, hut early tumours may be cured by radiotherapy, laser excision or more conven­tional excision. Recurrent disease following radiotherapy is managed surgically, and repair of the oropharynx may require regionally based myocutaneous flaps or free flaps with microvascular anastomosis. Neck dissection is required in a large proportion of cases of advanced disease. Postopera­tive dysphagia with aspiration, as a result of interference in the complex neuromuscular control of the second phase of swallowing, is a particular problem in these patients. More advanced tumours may also require additional resection of the mandible or an associated total laryngectomy, so this type of surgery is best carried out in a centre undertaking this work on a regular basis.

Lymphoma of the head and neck

  Lymphomas of the head and neck may arise in nodal or extranodal sires, and both Hodgkin’s disease and nonHodgkin’s lymphoma commonly present as lymph node enlargement in the neck. Hodgkin’s disease is rare in the oropharynx, but nonHodgkin’s lymphoma accounts for 15—20 per cent of tumours at this site in some countries. Most are of the B-cell type and have features in common with other tumours of MALT sires. Many of the lymphomas of the oropharynx have no demonstrable deposit elsewhere in the body when a full lymphoma investigation is carried out. On occasions, however, they may be secondary or coincident with deposits at other sires in the neck, the gastrointestinal tract, lung and the testes. Further evaluation with CT scanning of the thorax and abdomen, and bone marrow evaluation are essential. Radiotherapy is undoubtedly the treatment of choice for localised nonHodgkin’s lymphoma and may give control rates as high as 75 per cent at 5 years. For disseminated nonHodgkin’s lymphoma the treatment of choice is systemic chemotherapy. Combination chemotherapy is used in patients with an unfavourable histological type.