Original Article This work is licensed under the Creative Commons Attribution 4.0 License. Published by Pacific Group of e-Journals (PaGe) Histopathological Study of Tumor and Tumor Like Lesions of The Oral Cavity Introduction The oral cavity includes the lips, the hard palate, the upper and lower alveolar ridge, the anterior two thirds of the tongue, sublingual region ,the buccal mucosa, the retromolar trigone and the floor of the mouth (mylohyoid, digastric, geniohyoid muscles). [1] The oral cavity is the first part of digestive system and there are many types of tissues like bone of mandible and maxilla, epithelial tissue of oral mucosa, minor salivary glands, and odontogenic tissue; it is liable for different types of epithelial, mesenchymal and lymphoid tumors. [2] It is directly exposed to tobacco, alcohol, and food. [3] It is one of the most common sites for various tumors and tumor like lesions. [4] Tumor may originate from epithelial tissue, connective tissue, muscle tissue, nerve tissue and from vessels. [5] The most common oral lesions are candidiasis, recurrent herpes, recurrent aphthous stomatitis, mucocele, fibroma, pyogenic granuloma, hairy tongue, lichen planus, and leukoplakia which were confirmed by the large-scale, population based screening studies. [2,6] These lesions have been diagnosed clinically without biopsy. Other common lesions that are seen in routine work are those lesions which have arisen from the mandible, include both odontogenic and nonodontogenic origins and have varying degrees of destructive potential, as well as common benign cystic lesions which include periapical (radicular) cysts, follicular (dentigerous) cysts, and odontogenic keratocysts. [7,8] In addition, vascular tumors such as hemangioma and arteriovenous malformations are frequently seen in this site of the body. The benign tumors that have arisen from odontogenic structures and from mandible and maxilla include several types like cementoma, ossifying fibroma, Odontogenic myxoma, periapical cemental dysplasia. While the borderline and malignant tumors are ameloblastoma, ameloblastic carcinoma, ameloblastic fibrosarcoma, osteosarcoma, and metastatic tumors. [9,10] In the developing world oral cancer is the third most common cancer after stomach and cervical cancer. An estimated 378,500 new cases of intra-oral cancer are diagnosed annually worldwide. [11] The oral cavity is more accessible to complete examination; detection of precancerous and cancerous lesions can be done at earlier stage. Oral cancer has better prognosis and may be controlled effectively, if it is diagnosed at an early stage. [12] Biopsy of lesion of oral cavity is an easy outpatient procedure and gives definitive diagnosis. Babai Halder and Nirvana Rasaily Halder* Assistant Professor, Department of Pathology, Mamata Medical College, Rotary Nagar, Khammam-507002. Telangana. India ABSTRACT Background: The oral cavity is one of the most common site for various tumor and tumor like lesions. Development of oral cavity lesions are strongly linked with smoking. Hemangioma is the commonest benign tumor. Inflammatory fibrous hyperplasia is the commonest non- neoplastic reactive lesion. Squamous cell carcinoma (SCC) is most common among malignant lesions. Aims & Objectives: To study the histopathological patterns & variations of oral cavity lesions. Materials and Methods: A three year retrospective cross-sectional study by histopathological examination. Results: A total of 105 cases were subjected to histopathological examination. Among these, 28 cases (26.66%) were benign, 27 cases (25.71%) were malignant and 4 cases (3.80%) were pre-malignant lesions. Among the malignant lesions, SCC was most common (85.19%), while inflammatory fibrous hyperplasiawas most common among non- neoplastic lesions ( 45.65 %). Overall females were affected more than males (M: F=1: 1.1), though malignant lesions were more common in males. Malignant lesions were more common in older age group (mean age 52.26%), while non-neoplastic lesions were common in younger age group (mean age 37.87%). Malignant lesions were most common intongue (11 cases, 40.74 %), while benign lesions were most common in gingiva (10cases, 35.71% ). Conclusion: A variety of benign and malignant tumors occur in oral cavity. However, the origin and nature of the oral cavity lesions cannot be confirmed by clinical examination alone. Hence, histopathological examination is essential to confirm the diagnosis and malignant potential of the oral cavity lesions. Keywords: Oral Cavity, Benign Lesion, Malignant Lesion, Squamous Cell Carcinoma DOI: 10.21276/APALM.2460