The definitive anatomopathologic study of the sample removed revealed a pleomorphic adenoma or mixed tumor of the minor salivary glands (Fig. 4).

Discussion

Tumors of the salivary glands represent approximately 3% of the neoplasms of the head and neck in adults and around 8% in infants.¹ Of these, the pleomorphic adenoma is the most common tumor of the salivary glands representing between 40 and 70% of all the tumors affecting the major and minor salivary glands.^2,3

This tumor can appear at any age, although it is more prevalent between the 4^th and 6^th decades in life and it is slightly more frequent in women.⁴

The tumors that develop in the minor salivary glands represent 22% of all neoplasm of the salivary glands. Most of these are malignant and only 18% are benign. Within these the pleomorphic adenoma is the most common benign tumor.5 The most common place for it to appear when affecting the minor salivary glands is the palate (up to 50% of cases),5 followed by the upper lip, buccal mucosa, floor of the mouth, tongue, pharynx, retromolar area and nasal cavity.

Recently authors such as Jansisyamont and cols.,⁶ registered a series of 80 cases of minor salivary gland tumors, with a rate of 21.3% for pleomorphic adenomas with 39.5% affecting the palate.

Of the malignant tumors affecting the minor salivary glands, the most common was the cystic adenoid carcinoma.7

Clinically the pleomorphic adenoma appears as a painless, slow-growing nodule that is usually solitary. The skin or mucosa that surrounds it tends to have normal characteristics and the tumor does not adhere to deeper areas, except when it affects the hard palate. In these cases it can extend towards the periosteum and the underlying bone.⁴

With regard to its histological characteristics the pleomorphic adenoma has a mixture of epithelial and stromal elements. The stroma can be chondroid, myxoid or hyaline. The histogenesis of the tumor is related to a proliferation of cells with ductal and/or myoepithelial characteristics. Myoepithelial cell differentiation has an important role when determining the final appearance of mixed tumors. Most studies show a large variety of cells in mixed tumors, in some cases with epithelial characteristics and in others they are completely myoepithelial, and, between these two extremes, less differentiated cells may appear that have both ductal and myoepithelial elements.⁸

In order to diagnose these tumors, their clinical presentation is important, as this can help us determine their possible benign or malignant character. FNA is fundamental as is an incisional biopsy, and in this sense there are studies such as those carried out by Cerulli y cols.,⁷ that compare the efficiency of both techniques for establishing a preoperative diagnosis in palatal tumor cases. They reached the conclusion that FNA had a precision of 91.6% in the diagnosis of pleomorphic adenoma vs. cystic adenoid carcinoma when appearing in the minor salivary glands of the palate.

The potential for malignant transformation of the pleomorphic adenoma is estimated at around 6%, although this risk increases to 10% when the tumor has been evolving for more than 15 years.¹

Another therapeutic option would be postoperative radiotherapy that would permit reducing the rate of recurrence especially in those cases where the tumor affects the parapharyngeal space and complete resection is not possible.¹¹

Dirección para correspondencia
Silvia Gallana Alvarez
C/ Isbilia Nº 10
41907 Valencina de la Concepción (Sevilla), España
E-Mail: sgallana@hotmail.com

References

1. Unlu H, Celik O, Demir M, y cols. Pleomorphic adenoma originated from the inferior nasal turbinate. Auris Nasus Larynx 2003;30:417-20.        [ Links ]

2. Lopes MA, Kowalski LP, et al. A clinicopathologic study of 196 intraoral minor salivary gland tumours. J Oral Pathol Med 1999;28:264-7.        [ Links ]

3. Lopez-Cedrún JL, González-Landa G, Birichinaga B. Pleomorphic adenoma of the palate in children: report of a case. Int J Oral Maxillofac Surg 1996;25:206-7.        [ Links ]

4. Clauser L, Mandrioli S, Dallera V. Pleomorphic adenoma of the palate. J Craniofac Surg 2004;15:1026-9.        [ Links ]

5. Beckhardt RN, Weber RS, Zane R, y cols. Minor salivary gland tumors of the palate: Clinical and pathologic correlates of outcome. Laryngoscope 1995;105:1155-60.        [ Links ]

6. Jansisyanout P, Blanchaert H, y cols. Intraoral minor salivary gland neoplasm: a single institution experience of 80 cases. Int J Oral Maxillofac Surg 2002;31:257-61.        [ Links ]

7. Cerulli G, Giancarlo R, Perugini M, el al. Differential diagnosis between adenoid cystic carcinoma and pleomorphic adenoma of the minor salivary glands of palate. J Craniomaxillofac Surg 2004;15:1056-60.        [ Links ]

8. Regezi JA, Sciubba J, Jordan R. Salivary gland disseases. Oral Pathology Clinical Pathologic correlations (ed 4), Philadelphia, Saunders; 2003:196-8.        [ Links ]

9. To E, Tsang W, Tse G. Pleomorphic adenoma of the lower lip: Report of a case. J Oral Maxillofac Surg 2002;60:684-6.        [ Links ]

10. Spiro RH. Salivary neoplasm: overview of a 35 years experience with 2807 patients. Head Neck Surgery 1986;8:177-184.        [ Links ]

11. Bent JP, Dinges D. Pathologic quiz case- Minor salivary gland Pleomorphic adenoma of the parapharingeal space. Arch Otolaryngol Head Neck Surg 1992;118: 664-6.        [ Links ]