Introduction: Utilizing lower limit of bone marrow plasma cells (BMPCs) is the main existing criterion for diagnosis of multiple myeloma (MM). According to the revised international myeloma working group (IMWG) diagnostic criteria, the value of 10% is agreed among experts as the cutoff level for diagnosis. Symptomatic patients with BMPC above this value are identified as definite cases of MM. However, there are MM patients who have BMPC of less than 10%. Considering abovementioned cutoff could delay the diagnosis which in turn results in adverse effects in patients’ clinical course.
Case presentation: This study represented data of consecutive patients with 5% to 10% BMPC at our center from 2004 to 2013. MM existed among patients, as expected. This series provides a quantitative approximation of MM prevalence in these cases.
Conclusion: The reported patients’ status demonstrates the limitations of the abovementioned cutoff criterion in myeloma diagnosis, and emphasizes the importance of employing further diagnostic procedures in patients with marginal amounts of BMPC and high clinical suspicion. It has been shown that supplementary examination is especially required for two subgroups of patients with certain clinical and laboratory characteristics. The detail of the cases and results are thoroughly explained in the paper.