Plasma cell neoplasia is a lymphoid neoplastic proliferation of B cells. This denomination encloses multiple myeloma (MM), solitary bone plasmacytoma and extramedullary plasmacytoma. MM consists of a clonal proliferation of plasma cells based in the bone marrow, with various degrees of differentiation. Neoplastic cells usually produce great amounts of monoclonal light or heavy chains of immunoglobulin that can be detected in serum or urine. The disease is more frequently in men and the average age at diagnosis is about 60 years. The diagnosis is established by blood and urine exams and medullary biopsy. Patients may present renal failure, bone pain, fatigue, recurrent infections and nervous system dysfunction. Oral manifestations may be the first sign of MM, highlighting the importance of the dentist in the early diagnosis of the disease. Treatment involves mainly irradiation and chemotherapy and the prognosis is generally poor. This paper reports a case of a 65 years old black female who had a complaint of a painful mass in the maxilla that prompted a MM diagnosis. © Medicina Oral.125E344E347Seoane, J., Aguirre-Urizar, J.M., Esparza-Gomez, G., Suarez-Cunqueiro, M., Campos-Trapero, J., Pomareda, M., The spectrum of plasma cell neoplasia in oral pathology (2003) Med Oral, 8, pp. 269-280Lae, M.E., Vencio, E.F., Inwards, C.Y., Unni, K.K., Nascimento, A.G., Myeloma of the jaw bones: A clinicopathologic study of 33 cases (2003) Head Neck, 25, pp. 373-381Ozdemir, R., Kayiran, O., Oruc, M., Karaaslan, O., Kocer, U., Ogun, D., Plasmacytoma of the hard palate (2005) J Craniofac Surg, 16, pp. 164-169Currie, W.J., Hill, R.R., Keshani, D.K., An unusual cause of maxillary tuberosity enlargement (1994) Br Dent J, 177, pp. 60-62Kyle, R.A., Gertz, M.A., Witzig, T.E., Lust, J.A., Lacy, M.Q., Dispenzieri, A., Review of 1027 patients with newly diagnosed multiple myeloma (2003) Mayo Clin Proc, 78, pp. 21-33Gray, S.T., Antunovic, D.M., White, A.E., Non secretory multiple myeloma involving the maxilla: Report of a case with update of biology and new approaches to management (1997) Oral Oncol, 33, pp. 136-140Kyle, R.A., Multiple myeloma: An odyssey of discovery (2000) Br J Haematol, 111, pp. 1035-1044Zachriades, N., Papanicolaou, S., Papavassiliou, D., Vairaktaris, E., Triantafyllou, D., Mezitis, M., Plasma cell myeloma of the jaws (1987) Int J Oral Maxillofac Surg, 16, pp. 510-515Kyle, R.A., Multiple myeloma: Review of 869 cases (1975) Mayo Clin Proc, 50, pp. 29-40Epstein, J.B., Voss, N.J., Stevenson-Moore, P., Maxillofacial manifestations of multiple myeloma. An unusual case and review of the literature (1984) Oral Surg Oral Med Oral Pathol, 57, pp. 267-271Mateo Arias, J., Molina Martinez, M., Borrego, A., Mayorga, F., Amyloidosis of the submaxillary gland (2003) Med Oral, 8, pp. 66-70Reboiras Lopez, M.D., Garcia Garcia, A., Antunez Lopez, J., Blanco Carrion, A., Gandara Vila, P., Gandara Rey, J.M., Anaesthesia of the right lower hemilip as a first manifestation of multiple myeloma. Presentation of a clinical case (2001) Med Oral, 6, pp. 168-172Hsi, E.D., Yegappan, S., Lymphoma Immunophenotyping: A New Era in Paraffin-Section Immunohistochemistry (2001) Advances in Anatomic Pathology, 8, pp. 218-239Bayer-Garner, I.B., Prieto, V.G., Smoller, B.R., Detection of clonality with kappa and lambda immunohistochemical analysis in cutaneous plasmacytomas (2004) Arch Pathol Lab Med, 128, pp. 645-648Shin, J.S., Stopyra, G.A., Warhol, M.J., Multhaupt, H.A.B., Plasmacytoma with aberrant expression of myeloid markers, T-cell markers, and cytokeratin (2001) The Journal of Histochemistry & Cytochemistry, 49, pp. 791-792Rosai, J., (2004) Rosai and Ackerman's Surgical Pathology, pp. 2099-2105. , St Louis: Mosby CoDurie, B.G.M., Stock-Novack, D., Salmon, S.E., Finley, P., Beckord, J., Crowley, J., Prognostic Value of Pretreatment Serum-2 Microglobulin in Myeloma: A Southwest Oncology Group Study (1990) Blood, 75, pp. 823-830