Brazilian Journal of Case Reports 2024, 4, 3, 47-55. https://doi.org/10.52600/2763-583X.bjcr.2024.4.3.47-55 www.bjcasereports.com.br Case Report Carcinoma Ex Pleomorphic Adenoma - Report of a Rare Case in the Cheek Mucosa Luciane Santana Freitas ¹, Olegário Antônio Teixeira Neto 2, 3 , Leonardo Araújo de Andrade 4, 5 , Patrícia Freire Gas- paretto 6 , Cláudio Maranhão Pereira 7, * 1 Stomatology Specialist at Universidade Paulista, Brasília, DF, Brazil. 2 Assistant professor of Periodontics at UniEVANGÉLICA, Anápolis, GO, Brazil. 3 Assistant Professor of Periodontics at Universidade Paulista, Goiânia, GO, Brazil. 4 Professor of Oral Surgery at Universidade Paulista, GO, Brazil. 5 Professor of Oral Surgery at UNIGOYAZES, Trindade, GO Brazil. 6 Professor of Dental Prothesis at Universidade Paulista, Goiânia, GO, Brazil. 7 Professor of Stomatology at PUC, Goiás, Brazil. * Correspondence: claudiopereira@pucgoias.edu.br. Abstract: Carcinoma ex pleomorphic adenoma (CEPA) is a malignization of pleomorphic adenoma and often evolves silently. Its occurrence is rare and predominantly affects the major salivary glands, with the palate being the most common intraoral location. It is recognized as a condition with difficult clinical and pathological diagnosis, and histopathology remains the gold standard for definitive diagnosis. This study presents a primary CEPA in the buccal mucosa identified in a 69- year-old female patient. Less invasive tumors are associated with good prognosis; therefore, early recognition is important as they can become more aggressive, leading to more comprehensive ther- apies and reserved prognoses. Keywords: Pleomorphic adenoma; Carcinoma ex pleomorphic adenoma; Minor salivary glands. 1. Introduction Pleomorphic adenoma (PA) is a benign neoplasm of epithelial origin that represents, on average, 3% of head and neck tumors and 80% of salivary gland tumors. It occurs more frequently in the parotid gland, followed by the submandibular gland and minor salivary glands. Usually, it is well-circumscribed, slow-growing, painless, and firm to the touch, with or without encapsulation. The longer the PA persists, the higher the likelihood of malignization, leading to three subtypes of malignant mixed tumors: carcinosarcoma, me- tastasizing pleomorphic adenoma, and carcinoma ex pleomorphic adenoma (CEPA). Ap- proximately 1% to 7% of PAs transform into CEPA. CEPA is a rare malignant tumor, estimated to occur in 0.17 tumors per 1 million peo- ple per year, representing about 3% to 5% of all salivary gland neoplasms and 5% to 15% of malignant tumors of these glands. It predominantly affects the major salivary glands, with most cases observed in the parotid and submandibular glands. It rarely arises in mi- nor salivary glands, and when located in the oral cavity, the palate is the most commonly affected site. Diagnostic methods may include fine-needle aspiration biopsy (FNAB) and cytology, ultrasonography, computed tomography, and magnetic resonance imaging. FNABs are widely used for diagnosing salivary gland tumors and are considered easy, inexpensive, quick to perform, and well-accepted by patients. However, cytology from FNABs has low Citation: Freitas LS, Teixeira Neto OA, Andrade LA, Gasparetto PF, Pe- reira CM. Carcinoma Ex Pleomorphic Adenoma - Report of a Rare Case in the Cheek Mucosa. Brazilian Journal of Case Reports. 2024 Apr- Jun;04(2):47-55. Received: 28 November 2023 Accepted: 21 December 2023 Published: 2 January 2024 Copyright: This work is licensed un- der a Creative Commons Attribution 4.0 International License (CC BY 4.0).