Case Report Giant Parotid Pleomorphic Adenoma with Atypical Histological Presentation and Long-Term Recurrence-Free Follow-Up after Surgery: A Case Report and Review of the Literature Mohammed AlKindi , 1 Sundar Ramalingam , 1 Lujain Abdulmajeed Hakeem , 1 and Manal A. AlSheddi 2 1 Department of Oral and Maxillofacial Surgery, College of Dentistry, King Saud University, Riyadh, Saudi Arabia 2 Department of Basic Sciences, College of Dentistry, Princess Nourah Bint Abdulrahman University, Riyadh, Saudi Arabia Correspondence should be addressed to Sundar Ramalingam; sundar.ksu@gmail.com Received 5 July 2020; Revised 14 August 2020; Accepted 21 August 2020; Published 1 September 2020 Academic Editor: Pravinkumar G. Patil Copyright © 2020 Mohammed AlKindi et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Salivary gland tumors (SGT) comprise 3% of all head and neck tumors, are mostly benign, and arise frequently in the parotid gland. Pleomorphic adenoma (PA) is the commonest SGT, representing 60-70% of all benign parotid tumors. Clinically, parotid PA presents as irregular, lobulated, asymptomatic, slow-growing preauricular mass, involving both superficial and deep lobes, and could grow to gigantic proportions. Histologically, PA has epithelial and mesenchymal elements in chondromyxoid matrix and is managed surgically. Based on a review of 43 cases reported in English literature since 1995, giant parotid PA is reported as large as 35 cm (diameter) and 7.3 kg (resected weight). Although rare, 10 cases of malignant transformation were reported in the review. Surgical management included extracapsular dissection (ECD), superficial parotidectomy, and total parotidectomy for benign tumors, and adjuvant radiation or chemotherapy for malignant tumors. We further present the case of a 36-year-old healthy male with slow-growing and asymptomatic giant parotid PA, of 4-year duration. The patient presented with firm, lobulated preauricular swelling, provisionally diagnosed as PA based on radiographic and cytological findings. The tumor was resected through ECD, and the patient had uneventful postoperative recovery and a 7-year recurrence-free follow-up period. Histological examination revealed epimyoepithelial proliferation punctuated by chondromyxoid areas, with extensive squamous metaplasia and keratin cysts. To the best of knowledge from indexed literature, giant parotid PA is rarely reported in Saudi Arabia. In addition to its rarity, this case is reported for its benign nature despite atypical histological presentation, successful surgical management without complications, and long-term recurrence-free follow-up. Based on this report, clinicians must be aware of atypical histological presentations associated with PA and plan suitable surgical management and follow-up to avoid morbidity. Nevertheless, attempts must be made to diagnose and manage these lesions at an early stage and before they reach gigantic proportions. 1. Introduction Neoplastic lesions of the salivary glands are uncommon and comprise less than 3% of all reported head and neck tumors [1, 2]. Nearly 80% of the reported salivary gland tumors (SGT) are benign and occur predominantly in major salivary glands, with the parotid gland being the commonest site (70– 80%) [2, 3]. Often presenting as slow-growing, painless masses, tumors involving major salivary glands are rarely aggressive or malignant (<10%). On the contrary, tumors of minor salivary glands while occurring rarely have a prepon- derance to be malignant (80–90%) [2, 3]. Pleomorphic ade- noma (PA) is the commonest SGT, accounting for almost 60–80% of all benign SGT and 60–70% of all parotid gland tumors [1, 3]. Clinically, PA presents as an irregular, rubbery, lobulated, slow-growing mass without any associated pain or discomfort. The presenting complaint is typically related to unpleasant or unesthetic facial appearance, which when Hindawi Case Reports in Dentistry Volume 2020, Article ID 8828775, 18 pages https://doi.org/10.1155/2020/8828775