emia , ▁i . e . ▁in ▁patients ▁without ▁prior ▁history ▁of ▁a ▁pl asma ▁cell ▁d ys c ras ia ▁or ▁as ▁secondary ▁pl asma ▁cell ▁d ys c ras ia , ▁i . e . ▁in ▁patients ▁previously ▁diagn osed ▁with ▁a ▁history ▁of ▁its ▁prede cess or ▁d ys c ras ia , ▁multiple ▁my el oma . ▁The ▁two ▁forms ▁of ▁P CL ▁appear ▁to ▁be ▁at ▁least ▁partially ▁distinct ▁from ▁each ▁other . ▁In ▁all ▁cases , ▁however , ▁P CL ▁is ▁an ▁extremely ▁serious , ▁life - th re aten ing , ▁and ▁th era pe ut ically ▁challeng ing ▁disease . ▁ ▁Sign s ▁and ▁sympt oms ▁ ▁Primary ▁P CL ▁ ▁The ▁clin ical ▁presentation ▁of ▁primary ▁P CL ▁( p P CL ) ▁indicates ▁a ▁far ▁more ▁ag gress ive ▁disease ▁than ▁that ▁of ▁a ▁typical ▁multiple ▁my el oma ▁case ▁with ▁its ▁clin ical ▁features ▁being ▁a ▁combination ▁of ▁those ▁found ▁in ▁multiple ▁my el oma ▁and ▁ac ute ▁le uk emia . ▁Like ▁multiple ▁my el oma ▁patients , ▁p P CL ▁patients ▁exhib it ▁path olog ically ▁high ▁levels ▁of ▁mon oc l onal ▁pl asma ▁cells ▁in ▁their ▁b one ▁mar row ▁plus ▁a ▁m align ant ▁pl asma ▁cell - secret ed ▁circul ating ▁mon oc l onal ▁my el oma ▁protein , ▁either ▁Ig G , ▁Ig A , ▁a ▁light ▁chain , ▁or ▁none ▁in ▁ 2 8 - 5 6 %, ▁ 4 - 7 %,