Revista nº 802

177 Emilio Guirao Arrabal Non-secretory multiple myeloma has different characteristics from secretory multiple myeloma, that may lead to a delay in diagnosis tiple myeloma (MM) (70% neoplastic plasmatic cells: CD38 ++/+++, CD56 +, CD138+ and kappa IgG cytoplasmic; CD45 and CD117 nega- tive). Kappa and lambda light chains and kappa/lambda index were normal in both blood and urine samples. No immunofixation was detected. Final diagnosis: Non-secretory Multiple Myeloma (NSMM) as- sociated with spontaneous fractures. DISCUSSION MM is a neoplastic disease whose origin is in the bone ma- rrow infiltration by plasma cells that typically produce serum or uri- ne proteins(1). Immunologically, non-secretory MM differentiates into those that produce immunoglobulins and others that do not. Therefore we must differentiate those tumors that have a deficit in protein production (“non-producing”) from those who have a de- fect for protein secretion. Within the latter there is a subgroup that have the capacity to secrete small amounts of immunoglobulins (oligosecretory MM). Therefore we define as “true” NSMM as MM that does not produce immunoglobulins at all, given the current methods of immunofixation(2). This entity represents about 3% of all MM in some series(3). There is therefore confusion about the terminology and the current trend is to clearly establish the specific type of MM for every patient. As for the clinical manifestations, the non-secretory MM tends to manifest with moderate to severe osteoporosis and bone fractures that can be multiple sometimes, as in our case (4). Anae- mia is somewhat less frequent than in secretory MM and renal involvement is rare(2). In some series there seems to be a better prognosis of this subtype with respect to secretory MM(5). The absence of a monoclonal gamma globulins’ peak in pro- teinogram in NSMM can lead to difficulties in diagnosis. Clinicians may tend to perform some other explorations (endoscopies, PET- scans, etc.) in a patient with several osteolytic lesions and no suspi- cion for MM, in order to seek for a primary tumor. CONCLUSION This case seems extremely interesting, because this condi- tion must be in the differential diagnosis of secondary osteoporo- sis and multiple osteolytic processes, even when no monoclonal gammaglobulin’s peak in protein electrophoresis is found. We in- sist in the need to perform a bone-marrow study in these patients, even when there is no positivity for light chains or immunofixation. Compliance with Ethical Standards: This article is a clinical case report. No patient information or patients identification images are reported, therefore no infor- med consent was required. All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards. This case report has no funding. Conflictos de interés: Todos los autores declaran no tener ningún conflicto de interés. Fuentes de apoyo financiero: Ninguna. REFERENCES 1. Palumbo A, Anderson K. Multiple Myeloma. N Engl J Med. 2011;364(11):1046–60. 2. Lonial S, Kaufman JL. Non-secretory myeloma: a clinician’s guide. Oncology (Williston Park). 2013;27(9):924–928,930. 3. International Myeloma Working Group. Criteria for the classification of monoclonal gammopathies, multiple myeloma and related disorders. Br J Haematol. 2003;121:749–57. 4. Middela S, Kanse P. Nonsecretory multiple myeloma. Indian J Orthop. 2009 Oct;43(4):408–11. 5. Kyle RA, Gertz MA, Witzig TE, Lust JA, Lacy MQ, Dispenzieri A, et al. Review of 1027 patients with newly diagnosed multiple myeloma. Mayo Clin Proc. 2003;78(1):21–33. Image 1. Vertical right sacral wing fracture on computed tomography (arrow).