Role of Radiotherapy in Parotid Pleomorphic Adenoma: Two Case Reports and a Review of the Literature

Abstract

Pleomorphic adenoma is the most common benign salivary gland neoplasm (%75-80). It is found mostly in the parotid gland in middle-aged women. The optimal treatment is superficial or total parotidectomy with facial nerve preservation, which results in local control rates of 95% or higher. Radiotherapy (RT) is indicated for ositive margins, unresectable tumours, and multifocal recurrences after prior resection. Local control rates after RT for microscopic and gross residual tumour are approximately 80% to 85% and 40% to 60%, respectively. In this article, we share our experience of 2 cases of recurrent pleomorphic adenoma. Key Words: Pleomorphic Adenoma; Radiotherapy; Treatment.Parotis Pleomorfik Adenomunda Radyoterapinin Yeri: İki Olgu Sunumu ve Literatürün Gözden Geçirilmesi Özet Pleomorfik adenomlar tükrük bezlerinin en sık görülen iyi huylu neoplazmlarıdır (%75-80). Genelde orta yaşlı kadınlarda ve parotis bezinde bulunur. Optimal tedavi şekli fasial siniri koruyarak yapılan superfisyal veya total parotidektomidir. Cerrahi ile %95 ve üzerinde başarı vardır. Radyoterapi(RT) pozitif cerrahi sınırda, unrezektabl hastalıkta ve cerrahi sonrası multifokal nüksde kullanılır. RT sonrası lokal kontrol mikroskopik hastalıkta %80-85 ve gros rezidüel hastalıkta %40-60 arasındadır. Biz de bu makalede cerrahi sonrası nüks eden 2 olguyu adjuvan RT deneyimimizi paylaştık. Anahtar Kelimeler: Pleomorfik Adenom; Radyoterapi; Tedavi.Pleomorphic adenomas are the most common benign neoplasms of the salivary glands (75-80%) (1). The term pleomorphic defines the epithelial and connective tissue structures from which tumours originate. Although pleomorphic adenoma is often found in the parotid gland, it can also be seen in the submandibular, sublingual, or minor salivary glands. It is usually seen between 30-60 years of age and is more common in women than it is in men (2, 3). Patients usually present with complaints of painless, slow-growing masses. About 3-4% of pleomorphic adenomas can turn into carcinoma, causing metastases and even death (4). Rarely, benign pleomorphic adenomas can also metastasize (5). The etiology is unclear. A study conducted in Brazil on 60 submandibular pleomorphic adenoma cases reports negative results for both Ki-67 and p53 gene mutations (6). Hamada et al.'s study on 9 recurrent pleomorphic adenoma patients and 40 patients without recurrence after surgery examines mucin expressions like MUC1, MUC2, MUC4, MUC5AC, and MUC6 and, after observing increase in MUC1/DF3 expression (by p=0,011) in 4 of the 9 recurrent patients and 3 of the 40 patients without recurrence, it concludes that this indicator may be used as a marker in predicting recurrence after surgery (7).In this study, we aim to review 2 patients who experienced relapse after surgery along with a survey of the related literature.Case 1: A twenty-seven-year-old female patient was admitted to the hospital 6 years ago with swelling under the right ear. The CT imaging showed parotid masses. The patient underwent total parotidectomy due to paroti...