Hindawi Publishing Corporation Journal of Oncology Volume 2010, Article ID 202305, 10 pages doi:10.1155/2010/202305 Review Article Oral Lesions and Lymphoproliferative Disorders P. Castellarin, 1 G. Pozzato, 2 G. Tirelli, 3 R. Di Lenarda, 1 and M. Biasotto 1 1 Department of Dental Science, University of Trieste, 34127 Trieste, Italy 2 Department of Haematology, University of Trieste, 34142 Trieste, Italy 3 Department of Otorhinolaryngology, Head and Neck Surgery, University of Trieste, 34127 Trieste, Italy Correspondence should be addressed to M. Biasotto, m.biasotto@fmc.units.it Received 20 April 2010; Revised 13 July 2010; Accepted 26 July 2010 Academic Editor: Stefano Cascinu Copyright © 2010 P. Castellarin 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. Lymphoproliferative disorders are heterogeneous malignancy characterized by the expansion of a lymphoid clone more or less differentiated. At the level of the oral cavity, the lymphoproliferative disorder can occur in various ways, most commonly as lymphoid lesions with extranodal externalization, but sometimes, oral lesions may represent a localization of a disease spread. With regard to the primary localizations of lymphoproliferative disorders, a careful examination of the head and neck, oral, and oropharyngeal area is necessary in order to identify suspicious lesions, and their early detection results in a better prognosis for the patient. Numerous complications have been described and frequently found at oral level, due to pathology or different therapeutic strategies. These complications require precise diagnosis and measures to oral health care. In all this, oral pathologists, as well as dental practitioners, have a central role in the treatment and long-term monitoring of these patients. 1. Introduction Under the name of lymphoproliferative disorders various disease patterns are included which are characterized by the expansion of a lymphoid clone more or less differentiated. The application in recent times, of immunological methods for determining the phenotype of many cell components, together with the acquisitions of cytogenetic and molecular biology, as well as clinical behavior, have helped to relatively define a wide range of diseases that may present a hetero- geneous clinical and morphological picture. In fact, the last classification of lymphoproliferative disorders lists 40 types of lymphoproliferative syndromes to immunophenotype B and 23 to immunophenotype T [1]. At the level of the oral cavity, the lymphoproliferative disorder can occur in various ways, most commonly as lymphoid lesions with extranodal externalization, but sometimes, oral lesions may represent a localization of a disease spread [2]. Under the key research that sees lymphoproliferative disorders associated with injury or events at the oral cavity, the present paper proposes a comprehensive classification as listed in Table 1 and deeply described below. 2. Classification and Related Aspects of the Oral Pathologies Associated with Lymphoproliferative Disorders 2.1. Group 1: Primary Oral Lymphoproliferative Disorders Limited to the Oral Cavity that Will not Invade Other Body Districts. Primary extranodal involvement can be seen in 10% to 35% of cases of non-Hodgkin lymphomas. These locations include the gastrointestinal tract, skin, testicles, kidneys, and bones [3, 4]; the NHL of the central nervous system account for 1% of cases [5, 6]. Although the oral involvement of NHL is rare, they are the second most common oral malignant disease after oral squamous cell carcinoma [7, 8], constituting of 2.2% of all malignancies of the head-neck, 3.5% of intraoral malignancies, 5% of tumors of the salivary glands, and 2.5% of all cases of NHL [8]. Although every other site may be affected, Ring Waldayer is the most commonly involved [9]. The WHO system classifies NHL as indolent, aggressive, and highly aggressive. Indolent lymphoma accounts for 40% af all NHL with the most common type being follicular lymphoma; aggressive lymphoma accounts for approximately 50% of