Solitary Plasmacytoma. Presentation of 22 Cases of Two Centres from Buenos Aires, Argentina

Solitary plasmacytoma is a rare plasmatic cell tumor. Plasma cell neoplasia usually are generalized disease, in a small number of cases, less than 5 %, presents as a single bone lesion: solitary bone plasmacytoma (SBP) or develops outside the bone: extramedullary plasmacytoma (EMP).

Diagnostic criteria are: single bone tumor or single extramedullary mass of clonal plasma cells, normal bone marrow, no evidence of disseminated disease on skeletal survey, no anemia, hypercalcaemia or impairment of renal function, absent or low serum or urinary monoclonal immunoglobulin.

Material and Methods We present 22 patients treated at the Departament of Hematology of Marie Curie Hospital and Henry Moore Institute, 13 with SBP and 9 with EMP diagnosis. All were studied with the criteria of multiple myeloma. Prevalence of male 3.4/1 in both. Ages: SBP: 27–68 range, medium 47.23, EMP: 29–74 range, medium 55.

Locations of SBP: 5 in rachis (D3, D5, D7, D7, D8), 2 in clavícula, 2 in humerus, 1 in femur, sternum, etmoides, frontoparietal. The EMP: 7 in the head and neck: 3 in sinuses, 2 oropharynx, 1 uvula, maxillary mass (in area irradiated by NHL 7 years before), 1 lung + amyloid, 1 inguinal mass. Presence of a monoclonal paraprotein in serum/urine, was founded in 6 SBP (46%): 2 IgG kappa, 2 IgG lambda, 2 IgA lambda and in 2 EMP (22%): 1IgG lambda, 1 light chain lambda.

Results Treatment: SBP: in 10 RT + QT (VAD, Tal/Dex), 2 RT, 1 QT. Surgery was used to stabilize spine and/or long bones. EMP: 4 surgery + RT, 3 QT (VAD, Tal/Dex), 1 surgery + QT, 1 QT + RT. 8 patients underwent autologous bone marrow transplantation, 7 with SBP and 1 EMP, 5 of them aged under 36 years SBP: 3 patients achieved CR (10, 39, 77 months), 1 had local bone relapse, 2 without follow up, 3 of 7 transplanted patients relapsed, with evolution to multiple myeloma, 8 months, 23 months and 7 years later; the other 4 remain in CR, 27 to 82 months, media 36. EMP: 8 of 9 remain in CR, 2 to 120 months, media 35. One patient had a ileocecal relapse (initial site: oropharyngeal).

Conclusions Our series present male predominance, as reported by other studies. SBP prevail in axial skeleton and long bones in 61.5 %. Presents a worst development and prognosis, even though after ABMT. EMT was most frequently localized in head and neck (77,7%), in upper airways and oral cavity. The evolution was favorable, with only a single relapse. Diverse therapeutic methods happen to be useful. Low monoclonal paraprotein was present in 46 % of BPS and 22 % EMP.