Tehran University of Medical Sciences Journal of Craniomaxillofacial Research 2345-5489 8 4 2022 06 11 172 177 Maryam Jolehar Department of Oral & Maxillofacial Pathology, Faculty of Dentistry, Tehran University of Medical Sciences, Islamic Azad University, Tehran, Iran. Azadeh Zeinab Titidej Department of Oral & Maxillofacial Pathology, Dental Caries Prevention Research Center, Qazvin University of Medical Sciences, Qazvin, Iran. 2021 11 23 2022 04 22 Statement of the Problem: Mesenchymal tissue origin is one of the most common lesion in oral cavity. Most of these lesions are exuberant response to local irritation produces a soft tissue enlargement which are similar to neoplastic pathologic processes. Due to this diagnostic challenge the present study was conducted for reviewing the prevalence of soft tissue lesions. Search Strategy: The English articles in scientific databases including Google Scholar, Science Direct, Medline, and PubMed, published between 2007 and 2019, were searched by using relevant keywords including oral soft tissue lesion, oral mucosal lesion, neoplastic soft tissue lesion, reactive lesion, hyperplastic lesion and non-neoplastic soft tissue lesion. Finally, forty-nine articles were reviewed in this study. Conclusion: Findings showed that the most diagnosed lesions were benign in nature, and inflammatory in origin. Among this reactive/non-neoplastic lesions, fibrotic lesions, such as irritation fibroma or fibrous hyperplasia, were the most abundant lesions reported. There is a pronounced female predilection, and reactive lesions are most common in the fourth to sixth decades of life. Regarding the location of reactive lesions, the gingival mucosa was the most common site of involvement. Tumoral lesions with the origin of vascular, fibrotic and fat were the most commonly reported tumors. https://jcr.tums.ac.ir/index.php/jcr/article/view/393 https://jcr.tums.ac.ir/index.php/jcr/article/download/393/337