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Tonsil Cancer Symptoms

Pleomorphic adenoma of the tonsil

Pothula, Vijay B

Minor salivary gland tumours constitute less than 20% of all salivary gland neoplasms. Pleomorphic adenoma is one of the commonest benign tumour affecting salivary glands. Whilst benign tumours of minor salivary glands are uncommon, pleomorphic adenoma of the tonsil is distinguished by its rarity. Only five cases have been reported in the literature so far. We report a case of pleomorphic adenoma of the tonsil presenting as unilateral enlargement of tonsil and review the literature.

Keywords: Minor salivary glands; Pleomorphic Adenoma; Tonsil

Introduction

Over 50% of intra oral salivary gland tumours occur on the palate.1 The other intra oral sites are lips, buccal mucosa, tongue, floor of the mouth and retromolar trigone. Only five cases of minor salivary gland tumours affecting the tonsil have been described in the literature.2,3 Here we report a case of minor salivary gland tumour affecting the tonsil and review the literature.

Case Report

A 54 year old lady presented to the ENT outpatient department with recurrent sore throats and a choking sensation of a few years duration. There was no history of dysphagia, loss of weight or heart burn. She was not a smoker. Her general health was good and she was not on any medication. Examination of the throat revealed significant enlargement of the left tonsil, and was twice the size of the right tonsil. There was no ulceration of the mucosa. She had no palpable glands in the neck and the rest of the ENT examination was normal. She underwent a tonsillectomy, and the whole tonsil was easily dissected out without any adherence to the deeper tissues. The specimen was sent for histological examination. Histology showed a pleomorphic adenoma arising from a minor salivary gland in the tonsil with a predominantly myxochondroid pattern (Fig. 1). The patient was followed up in the outpatient department without any need for further treatment and 4 years after surgery she remains free of symptoms and with no signs of recurrence.

Discussion

Salivary gland tumours represent about 3% of all neoplasms.4 Tumours of the minor salivary glands comprise less than 20% of salivary gland neoplasms.3,5-7

Eveson et al reported an incidence of 46% of minor salivary gland tumours being malignant or potentially malignant while Issacson et al in their series of 201 intra oral tumours reported an incidence of only 27.5% of malignant neoplasms.2,3 Choudary et al in his personal series of 94 cases of intra oral tumours found 54% to be malignant. He also reviewed the published literature on intra oral minor salivary gland tumours of 1320 cases and found 39.4% of them were malignant with a predominance of benign minor salivary gland tumours.5 Quan et al in his study of 112 cases of minor salivary gland tumours found 46.1% being benign and 53% were malignant tumours.8 Nagler et al found an incidence of 50.8% benign tumours in minor salivary glands among which 41.7% were pleomorphic adenoma.9 Jones et al reviewed the seven reported series, and found 35% of minor salivary gland tumours were benign and 46% malignant.10 Among the benign tumours of minor salivary glands pleomorphic adenoma is the commonest.2,5,6,8-11

The minor salivary glands have been estimated to number between 600 and 1000. They are small, independent, predominantly mucous glands that are found in every part of the upper respiratory tract. The majority of the minor salivary glands are located in the palate, while the others are found in the submucosa of the uvula, inner surface of the lips, around the opening of the parotid duct, in the mucous membrane of the cheek, floor of the mouth, palatoglossal folds, superior pole of the tonsils (Weber's glands), on the inferior surface of the tongue, near the frenulum of tongue, and within the palatine tonsil.

Minor salivary glands of mucinous type are also located in the nose, paranasal sinuses, the larynx, trachea and bronchi. The commonest site of minor salivary gland tumours is the palate followed by lip, buccal mucosa, tongue and pharynx.2,11 A review of the English literature have shown only five benign salivary gland tumours of the tonsil to be reported so far. Of these three are in the series by Eveson et al and the other two by Issacson et al, all of them being pleomorphic adenomata.2,3 Interestingly all the minor salivary gland tumours affecting the tonsil reported by Spiro et al in 1973 and Spiro in 1986 are malignant, which is not the case in other reported series (Table 1).6,12 Pleomorphic adenoma is a benign tumour arising from intercalated duct cells and myoepithelial cells. This tumour was originally called mixed salivary tumour because it was thought to contain epithelial and chondroid elements and hence was thought to be of mixed origin. It is now believed that it is not a true mixed tumour but is of solely epithelial origin and the connective tissue appearances are secondary.13

Noguchi et al in an attempt to resolve the origin of pleomorphic adenoma from either epithelial or mesenchymal tissue, conducted a clonal analysis of pleomorphic adenoma and hypothesised that these two elements have a common single cell of origin.14

The diagnosis of pleomerphic adenoma in a unilaterally enlarged tonsil is difficult in the first instance due to its rarity of incidence. The differential diagnoses of a neoplastic tonsil enlargement are lymphoreticular tumours, squamous cell carcinoma or a parapharyngeal space tumour pushing the tonsil medially.

Pleomorphic adenoma is known to produce recurrence either due to spillage, inadequate removal or enucleation at the time of operation, but is not known to produce distant metastasis.11 Beckhardt reviewed 33 patients of benign salivary gland tumours of palate, and showed no evidence of recurrence.1

Surgery in the form of tonsillectomy is diagnostic and also forms the mainstay of the treatment for pleomorphic adenoma of the tonsil. Due to very few reported cases of pleomorphic adenoma of the tonsil, we suggest tonsillectomy with long term follow up as an adequate treatment of this condition, as in our case.

References

1. BECKHARDT.R.N., WEBER.R.S., ZANE.R.S., et al (1995) Minor Salivary Gland Tumours of the palate; clinical and pathologic correlates of outcome; Laryngoscope 105(11): 1155-60.

2. SNOW.G.B. (1979) Tumours of the parotid gland. Clinical Otolaryngology 4: 457-468.

3) CHOUDARY.A.A., VICKERS.R.A., GORLIN.RJ., (1961). Intra oral minor salivary gland tumours. An analysis of 1414 cases; Oral Surgery 14: 1194-1226

4. SPIRO.R.H., KOSS.L.G., HAJDU.S.I., STRONG.E.N. (1973); Tumours of minor salivary gland origin. A Clinico pathologic study of 492 cases. Cancer 31(1): 117-129.

5. MAIN.J.H., McCOMB.R.J., STRONG.E. (1976); Salivary gland tumours; Review of 643 cases. Journal of Oral Pathology 5: 88-102.

6. ISSACSON.G., SHEAR.M. (1983); Intra oral salivary gland tumours, a retrospective study of 201 cases. Journal of oral pathology; 5: 57-62

7. EVESON.J.W., CAWSON.R.A. (1985); Tumours of minor ( oropharyngeal ) salivary glands: A demographic study of 336 cases Journal of oral pathology 14: 500-509

8. QUAN.M.D., YAN.Y.G. (1987); Tumours of the minor salivary glands; A clinico pathological study of 243 cases. Acta Otolarygologica (Stockh); 103: 325-331.

9. NAGLER.R.M., LAUFER.D. (1997); Tumours of the major and minor salivary glands: Review of 25 years of experience. Anticancer Research; 17:701-7088)

10. JONES.A.S., BEASLEY.N.J.P., ET AL. (1998); Tumours of the minor salivary glands. Clinical Otolaryngology; 23: 27-33.

11. LOPES.M.A, KOWALSKI.L.P., ET AL (1999); A clinicopathologic study of 196 intraoral minor salivary gland tumours. J Oral Pathol Med: 28(6): 264-7.

12. SPIRO.R.H. (1986); Salivary neoplasms; Overview of a 35 year experience with 2807patients. Head and neck surgery. Jan/Feb: 177-184.

13. McGEE. J.O'D., ISSACSON. P.C., WRIGHT. N.A. (1992); Oxford Text book of Pathology; volume 2 a; Pathology of systems; Oxford University Press; 1075-1076.

14. NOGUCHI, S., AIHARA, T., ET AL. (1996); Demonstration at monoclonal origin of parotid gland pleomorphic adenoma. Cancer: volume 77; (3): 431-435.

Vijay B. Pothula F.R.C.S. (Orl)

John Mathews F.R.C.S. (Orl)

S.E. Kent F.R.C.S.

Department of Otolaryngology,

Warrington Hospital NHS Trust,

Lovely Lane,

Warrington

WA51QG

United Kingdom

Correspondence:

J. Mathews