Oral melanocytic nevi: a clinicopathologic study of 100 cases Leticia Ferreira, DDS, MS, a,b Bruno Jham, DDS, MS, PhD, c,d Rouba Assi, DDS, MPH, a Allison Readinger, MD, e and Harvey P. Kessler, DDS, MS f Objective. The purpose of this study was to evaluate the clinical and histopathologic features of oral melanocytic nevi (OMN). Study Design. One hundred cases of OMN were retrieved from the files of two oral pathology services, and the data were analyzed with regard to histologic type and clinical features. Results. Intramucosal nevus was the most common type (61%), followed by common blue nevus (23%), compound nevus (7%), and junctional nevus (3%). Combined nevus and cellular blue nevus were rare (2% each). The hard palate was the most commonly affected site (33%), followed by the buccal mucosa (18%), vermilion border of the lip (18%), and gingiva (15%). An interesting case of intramucosal nevus with lipomatosus-like changes and neurotization and two cases of oral dysplastic nevus are also reported. Conclusions. Intramucosal and common blue nevi are the most common types of OMN. Dysplastic nevus, which is recognized as a marker for melanoma in the skin, can rarely involve the oral cavity. Accordingly, dentists, especially oral and maxillofacial pathologists, should become familiar with the clinical and histopathologic features of this entity. (Oral Surg Oral Med Oral Pathol Oral Radiol 2015;120:358-367) Solitary pigmented lesions of melanocytic origin, other than the melanotic macule, are uncommon in the oral mucosa. These include melanoacanthoma, melanoma, and oral melanocytic nevus (OMN). 1 OMN are benign neoplasms composed of cells derived from the neural crest, often labeled nevus cells. 2 These melanocytic cells are found in the skin and mucous membranes, including the oral mucosa. 3 Although melanocytic nevi are frequently found on the skin, OMN are uncommon. The etiology and pathogenesis of OMN are poorly understood, with most of the information found in the literature being derived from small case report studies. 4 Thus, the purpose of this study was to describe the clinical and histopathologic features of 100 cases of OMN, retrieved from the files of the oral pathology services of Texas A&M University Baylor College of Dentistry, Dallas, and University of Maryland Dental School, Baltimore. MATERIALS AND METHODS The materials were retrieved from the files of the oral pathology services of Texas A&M University Baylor College of Dentistry in Dallas, Texas, and the Univer- sity of Maryland Dental School in Baltimore, Mary- land. All cases coded as melanocytic nevus between 1983 and February of 2010 were retrieved from the files of the services. All skin nevi, including lip lesions involving the skin, were excluded from the study. Clinical records were reviewed, and information, including patients’ age, gender, and race; lesions’ location, size, color, and configuration; and clinical provisional diagnoses, was harvested. Formalin fixed, paraffin-embedded tissue samples from all patients were available and obtained from the pathology ar- chives at both institutions. The microscopic features were reviewed based on one 5-mm hematoxylin and eosinestained section for each case. Cases were Part of the results of this clinicopathologic study was presented as an oral abstract at The American Academy of Oral and Maxillofacial Pathology 64th Annual Meeting, in Tucson, Arizona, in 2010. However, in the original study, we only had 84 cases of oral mela- nocytic nevi that were retrieved from the files of the oral pathology biopsy service at Texas A&M University Baylor College of Dentistry, in Dallas. In the current manuscript, we have added more cases of melanocytic nevi that were retrieved also from the files of the oral pathology biopsy service at the University of Maryland Dental School in Baltimore, Maryland. a Department of Biomedical Sciences, Texas A&M University Baylor College of Dentistry, Dallas, Texas, USA. b Assistant Professor, Department of Dental Practice, University of the Pacific Arthur A. Dugoni School of Dentistry, San Francisco, Cali- fornia, USA. c Department of Oncology and Diagnostic Sciences, School of Dentistry, University of Maryland, Baltimore, Maryland, USA. d Assistant Professor, College of Dental Medicine Illinois, Midwestern University, Downers Grove, Illinois, USA. e Pathologists’ Biomedical Laboratories, LLP, Baylor University Medical Center, Dallas, Texas, USA. f Department of Diagnostic Sciences, Texas A&M University Baylor College of Dentistry, Dallas, Texas, USA. Received for publication Sep 5, 2014; returned for revision May 7, 2015; accepted for publication May 11, 2015. Ó 2015 Elsevier Inc. All rights reserved. 2212-4403/$ - see front matter http://dx.doi.org/10.1016/j.oooo.2015.05.008 Statement of Clinical Relevance Epidemiologic data on oral melanocytic nevi is limited. This manuscript reports 100 cases of oral melanocytic nevi, including, for the first time in the literature, two cases of oral dysplastic nevi. 358 Vol. 120 No. 3 September 2015