Differentiation of multiple myeloma and metastases: Use of axial diffusion-weighted MR imaging in addition to standard MR imaging at 3T.

BACKGROUND: Metastasis and multiple myeloma are common malignant bone marrow lesions which may be difficult to distinguish because of similar imaging findings. The purpose of this study was to determine the value of adding diffusion-weighted imaging (DWI) to standard MR imaging to differentiate multiple myeloma from metastasis. METHODS: 25 patients with metastasis and 18 patients with multiple myeloma underwent 3T MR imaging with DWI (b = 0, 800 s/mm2) were enrolled. They all had pathologically confirmed bone lesions and were in a treatment naïve state. Two readers who were blind of final diagnosis measured the average ADC (ADCav) and minimum ADC (ADCmin) on the DWI. They then estimated the diagnosis, based on the standard MR imaging and measured ADC values. Another reader performed histogram analysis on the whole tumor volume and obtained mean ADC (ADCvol), standard deviation (SDvol), skewness, and kurtosis. Comparison of the obtained values from DWI was performed by the t-test or Mann-Whitney U test. The receiver operating characteristic (ROC) curve with areas under the curve (AUC) was used to obtain the cut off values and to evaluate the diagnostic performance of the two readers. RESULTS: ADCav, ADCmin, and ADCvol of multiple myeloma were significantly lower than those of metastasis: ADCav, 752 µm2/sec versus 1081 µm2/sec; ADCmin, 704 µm2/sec vs 835 µm2/sec; ADCvol 761 µm2/sec vs 1184 µm2/sec (p < .001). In histogram analysis, ADC values of multiple myeloma showed narrow distribution than metastasis: SDvol, 144 vs 257 (p < .001). Areas under the receiver operating characteristic curve was significantly higher with additive DWI than standard MR alone: 0.762 vs 0.953; 0.706 vs 0.950 (p < .05) for two readers. CONCLUSIONS: This study suggested that the addition of axial DWI to standard MR imaging can be helpful to diagnose multiple myeloma from metastasis at 3T.

[Serum free light chains for diagnosis and follow-up of multiple myeloma].

BACKGROUND: Free light chain (FLC) is widely used to evaluate B-cell proliferative diseases. Herein, we estimated the clinical usefulness of serum FLC in multiple myeloma (MM). METHODS: Fifty-one patients were enrolled. We performed FLC analysis, protein electrophoresis (PEP), and immunofixation electrophoresis (IFE). FLC was measured using Toshiba 200 FR Neo with FREELITE, and kappa/lambda (kappa/lambda) ratio was calculated. We compared these parameters in 41 patients with increased FLC before and after bortezomib treatment. Complete response (CR) was defined as the disappearance of monoclonal (M) protein in serum and/or urine as measured by IFE. Partial response (PR) was defined as >or=50% reduction of serum M protein. Early objective response (EOR) included both CR and PR. Minimal response (MR) was defined as 25-49% reduction of M protein and stable disease (SD) as <25% reduction. RESULTS: Forty-one (80.4%) of the 51 patients studied revealed increment of FLC and the five patients with no increment revealed an abnormal kappa/lambda ratio. Especially, all of the light chain myeloma and non-secretory myeloma showed increased FLC concentrations. Among the patients with EOR, 72.4% (21/29) showed a normal or subnormal FLC concentration after the first cycle of treatment. Otherwise, PEP and IFE normalized in 24.1% (7/29) and 24.1% (7/29), respectively. The ratio of decreased FLC after the first cycle of treatment was significantly different between EOR and other response groups (MR, SD) (90.6% vs 51.8%, P=0.011). CONCLUSIONS: FLC was considered as a good diagnostic method in complement with PEP and IFE in MM, especially in light chain myeloma or non-secretory myeloma. Moreover, FLC is a useful monitoring tool because it reflects therapy results more rapidly owing to a short serum half-life.

Case report: acute promyelocytic leukemia with +der(17)t(15;17) detected by fluorescence in situ hybridization (FISH).

We describe an unusual case of acute promyelocytic leukemia with +der(17)t(15;17) as the additional cytogenetic abnormality and with t(15;17) defined by fluorescence in situ hybridization (FISH) using a PML/RARA dual color, dual fusion translocation probe. By performing a step-by-step, complementary approach to evaluate unusual chromosomal abnormalities, we detected RARA/PML fusion on a marker chromosome similar to chromosome 17.

Evaluation of early post-transplant leukocyte recovery using the undiluted erythrocyte lysing technique.

The undiluted erythrocyte lysing technique was evaluated to see if it provides more accurate total leukocyte counts and differential leukocyte counts of severely leukopenic blood samples, in order to detect the onset of hematopoietic recovery after stem cell transplantation. Leukocyte counts using the conventional automated cell counting technique were found to be inaccurate, especially in blood samples with total leukocyte counts < 500/microl. In cases where the difference between results by the two methods was >100/microl, a positive correlation was found between the difference value and the blood reticulocyte count (r = 0.39, p = 0.002). Hematopoietic recovery after stem cell transplantation in a group of patients with chronic myelogenous leukemia (CML) was different from that of non-CML groups. In the CML group, the initial leukocyte counts were higher and the number of days until neutrophil recovery was higher than in the non-CML groups. Also, the day on which the absolute neutrophil count (ANC) exceeds 100/microl could serve as an indicator of neutrophil recovery. This study shows that the undiluted erythrocyte lysing technique can be used to count leukocytes accurately, especially in severely leukopenic samples. This new method can detect neutrophil recovery at ANC > 100/microl, as well as at an earlier date than the conventional method.