Mantle cell lymphoma represents 5–10% of all non-Hodgkin lymphomas. The chromosomal translocation t(11;14)(q13;q32) that juxtaposes the CCND1 gene to the IGH gene, resulting in overexpression of cyclin D1, is the genetic hallmark of the disease. It is subclassified as conventional mantle cell lymphoma or non-nodal leukemic mantle cell lymphoma, the latter representing a less aggressive clinical variant of the disease. The in situ mantle cell neoplasia is considered a very rare and indolent entity. Mantle cell lymphoma more often affects elderly males, and the lymph nodes are the most affected locations. Extranodal manifestations are found in approximately 25% of the cases, especially in the gastrointestinal tract, ocular adnexal region and lungs. In the oral cavity the tumor usually affects the palate, causing an asymptomatic non-ulcerated swelling. Multiple simultaneous lesions affecting different sites of the oral cavity can be found. The overlying mucosa may be normal-colored or may show a bluish to purple color. Microscopically, the neoplasm shows a diffuse growth pattern composed of small to medium-sized cells, with strong positivity for Cyclin D1 in almost 95% of the cases. Patients’ prognosis has improved significantly during the last years, but it is still considered a very heterogeneous and incurable disease.