99mTc-MIBI scintigraphy in the diagnosis of multiple myeloma.

POLSKIE ARCHIWUM MEDYCYNY WEWNĘTRZNEJ 2016; 126 (3) MM is characterized by malignant proliferation of clonal plasma cells and excessive formation of monoclonal immunoglobulin.1 99mTc-MIBI is a radiotracer commonly used in myocardial perfusion imaging (FIGURE 1C). In literature, there have been reports on the use of 99mTc-MIBI in the diagnosis of MM since 1996.2 In a multicenter study conducted in Italy between the years 2001 and 2005 on a group of 397 patients, sensitivity to detect changes in MM using 99mTc-MIBI was assessed as 77% compared with 45% using radiographic images.2 GuangUei et al1 compared the sensitivity to detect changes in MM using radiography, 99mTc-MIBI scintigraphy, and fluorodeoxyglucose positron emission tomography (PET-FDG). In terms of abnormalities in the skeletal system, the sensitivity of radiography was 80%; of 99mTc-MIBI, 80%; and of PETFDG, 93.3%; in terms of abnormalities in soft tissue, the sensitivity of radiography was 21.1%; of 99mTc-MIBI, 68.4%; and of PET-FDG, 89.5%; and in terms of bone marrow infiltration, the sensitivity of radiography was 0%; of 99mTc-MIBI, 80%; A 59-year-old patient was admitted to an internal medicine department because of osteolytic lesions in the cervical and thoracic spine, identified on computed tomography (CT) and magnetic resonance imaging and suspected to be a metastasis (FIGURE 1A). The patient underwent chest, abdominal, and pelvic CT, bone scintigraphy with technetium-99m methylene diphosphonate, gastroscopy, and colonoscopy. None of the tests showed the primary focus of the tumor. Laboratory tests revealed increased erythrocyte sedimentation rate (47 mm/h; reference range, 3–8 mm/h) and total prostate-specific antigen levels (9.24 ng/ml; reference range, 0.00–4.00 ng/ml). Other possible causes of osteolysis were excluded. Multiple myeloma (MM) was suggested but protein electrophoresis showed no abnormalities, and urine samples were negative for Bence–Jones protein. β2 microglobulin levels were increased (2.41 mg/l; reference range, 0.80–2.20 mg/l), and immunofixation of serum proteins revealed equivocal results. The patient underwent whole-body scintigraphy after an intravenous administration of methoxyisobutylisonitrile labeled with 99mTc (99mTcMIBI). Accumulation of 99mTc-MIBI in the sternum and thoracic spine, and partially in the lumbar spine, suggested plasmocytic infiltration in the area (FIGURE 1B). A consulting hematologist considered MM as an unlikely final diagnosis until the results of bone marrow biopsy were received. However, in bone-marrow preparation collected from the sternum, the infiltration of plasma cells was found (23%), which confirmed MM. The patient was transferred to a hematology department for treatment, where after some additional tests, the final diagnosis of MM, lambda light chain disease stage IIIA according to the International Staging System, was established. The patient was referred for treatment with bortezomib and autologous hematopoietic cell transplantation. Correspondence to: Olgierd Chrabański, MD, Clinica Medica – Zakład Medycyny Nuklearnej, ul. Edukacji 102, 43-100 Tychy, Poland, phone: +48 32 218 21 21, e-mail: [email protected] Received: November 8, 2016. Revision accepted: January 22, 2016. Published online: February 12, 2016. Conflict of interests: none declared. Pol Arch Med Wewn. 2016; 126 (3): 190-192 doi: 10.20452/pamw.3290 Copyright by Medycyna Praktyczna, Kraków 2016 CLINICAL IMAGE