Top Ten Lymphoproliferative Lesions Not to Miss When Evaluating Oral Ulcer Biopsies

Background Oral ulcers represent a full thickness loss of the mucosal epithelium leading to exposure of the submucosal connective tissue. These are common and usually self-limited lesions, although they may sometimes result from neoplasms, most commonly squamous cell carcinoma. Lymphoproliferative disorders may be difficult to diagnose in apthous ulcers since they mimic reactive inflammation. Methods This review presents ten rare oral lymphoid proliferations which should not be missed when assessing oral ulcer biopsies. Results The ten lesions include several with diagnostic cells which look similar to the histiocytes of a reactive inflammatory ulcer, including Rosai–Dorfman disease, reticulohistiocytoma, Langerhans cell histiocytosis, and traumatic ulcerative granuloma. Other lesions, such as EBV-positive mucocutaneous ulcer, extranodal marginal zone lymphoma of mucosal-associated lymphoid tissue, and plasmablastic lymphoma have lymphoid and/or plasma cell differentiation that mimic the reactive lymphocytes and plasma cells found in reactive ulcers. Two dendritic cell lesions, follicular dendritic cell sarcoma and blastic plasmacytoid dendritic cell neoplasm, both have distinct phenotypes which are required to make an accurate diagnosis. Conclusion Each of these lesions are diagnosed by evaluating their histology, along with their phenotypic profile, which is sometimes enhanced by pertinent molecular findings.