Page 438 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

422 PART 6 ■ Neoplastic Disorders

Monoclonal B-Cell Lymphocytosis P53, y be tre te with ibrutinib n i el lisib. Eligible

p tients y be consi ere or llogenic bone rrow
Monoclon l B-cell ly phocytosis (MLD) is now known to tr nspl nt tion.

prece e virtu lly ll c ses o CLL/SLL. Although the newly

up te Worl He lth Org niz tion (WHO) will ret in Hairy Cell Leukemia (HCL)

the current criteri or MLD, it oes e ph size th t the

“low count” MLD peripher l bloo leukocyte count o less Hairy cell Leukemia (HCL) is n unco on chronic ly pho-

th n 0.5 × 10 /L ust be istinguishe ro “high count” proli er tive isor er o the B-ly phocyte type. T is ture
9
MBL. B-cell lign ncy is i gnose b se on clinic l e tures,

“Low count” MBL h s signif c nt i erences ro CLL orphology, n phenotyping.

with extre ely li ite , i ny, ch nce o progression. “High

count” MBL nee s to be onitore . It rese bles the pheno- Cytogenetics

typic n epigenetic/ olecul r e tures o R i st ge 0. BRAF V600E is the genetic lesion oun in l ost ll c ses

o h iry cell leuke i but not in HCL v ri nt or other s ll

B-Cell Prolymphocytic Leukemias B-cell ly phoi neopl s s. Recently, ut tions in MAP2K1

th t enco es MEK1, which is ownstre o BRAF, h ve
B-cell prolymphocytic leukemias (B-PLLs) re r re ly phoi been reporte in l ost h l o HCL-v ri nt c ses n in the

neopl s s with poor prognosis. o istinguish it ro jority o HCL th t use IGHV4-34 n th t, like HCL-v,

CLL, it requires ore th n 55% o circul ting ly phoi cells l ck BRAF V600E ut tions.

to h ve the orphology o proly phocyte.

Epidem iology
Epidem iology
HCL is uch ore co on in les th n in e les. It usu-
B-PLLs re r re n ccount or less th n 2% o ly phoi lly ects p tients ol er th n 30 ye rs o ge.

leuke i s.

T is or o leuke i occurs in ol er ults with Clinical Signs and Sym ptom s

e i n ge in the 60s ( ge 69 or B cell). M les h ve higher

inci ence o PLL leuke i . Initi l p tient sy pto s inclu e tigue, ne i , leukocyto-
peni , thro bocytopeni , spleno eg ly, n rrow f bro-

Clinical Signs and Sym ptom s sis. P ncytopeni is co on. Blee ing n in ection c n be
present. T e bone rrow y beco e f brotic; there ore,
B-PLLs present with spleno eg ly n ly phocytosis. bone rrow spir tes requently re unsuccess ul ( ry

B-PLLs re typic lly ggressive, but subset o p tients y t p). re t ent with inter eron y h ve positive e ect on

exhibit n in olent ph se o v ri ble length. bone rrow f brosis.

Laboratory Findings
Laboratory Findings
B-PLL c n be istinguishe ro other - n B-cell leuke-

i s by ev lu tion o bloo cell orphology, i unophe- Di gnosis o HCL inclu es orphologic l ppe r nce o the

notyping, n olecul r genetics. ly phocytes, cytoche ic l st ining, n i unocytologi-

Proly phocytic leuke i is ch r cterize by l rge nu - c l ch r cteriz tion by ow cyto etry.

ber o ly phocytes with the i ture e tures o proly - HCL is so n e bec use o the ppe r nce o f ne, h ir-

phocytes in the peripher l bloo . B-PLL ly phocytes h ve like, irregul r cytopl s ic projections th t re ch r cteristic

roun nucleus, o er tely bun nt cytopl s , n istinct o ly phocytes (Fig. 22.4) in this ise se. Cytopl s ic pro-

“punche -out” nucleolus. T e pro inent centr l nucleolus jections re not lw ys obvious in HCL n in so e c ses

llows PLL to be istinguishe ro CLL/SLL. T e tot l leu- (e.g., rti ctu lly in other ly phoi neopl s s or re ctive

kocyte count is gre ter th n 100 × 10 /L. Proly phocytes cells) re not specif c or HCL.
9
ust excee 55% o ly phoi cells in the peripher l bloo . Morphologic lly, HCLs re l rge with o er tely l rge

Most p tients h ve ise se o B-cell r ther th n -cell nuclei. So eti es, the sl te-blue cytopl s is v cuol te .

origin. B-cell PLL is positive or p n-B-cell rkers, CD20, Te nucleus is requently ov l or slightly cle e n y

CD19, CD22, n FMC7. In ition, CD24 is positive, CD5 be convolute with ho ogeneous chro tin p ttern. T e

is v ri ble, n CD23 is neg tive. T e cells ispl y strong SIg. cytoche ic l e tures o HCL inclu e strong ci phosph -

Cytogenetics reve l t(8;14), el 17p but no t(11;14). Molecul r t se re ction th t is not inhibite by t rt ric ci or t rtr te-

genetics in ic te CMYC n P53 ut tion. Distinguishing resist nt ci phosph t se ( RAP) st in. RAP positivity c n

PLL ro ntle cell ly pho (MCL) with leuke ic v ry with ise se progression. In ition, ollowing inter-

involve ent requires exclu ing t(11;14). eron ther py, enzy e ctivity in the h iry cell y be RAP
neg tive.
Treatm ent Te i unologic l rkers inclu e CD19+, CD20+,

First-line ther py or p tients with B-PLL is co bin tion CD22+, CD24+, n CD25+ re ctivity to the onoclon l

o purine n log-b se che oi unother py. P tients ntibo y th t recognizes the interleukin-2 ( c) receptor. In

with B-PLL, especi lly p tients with bnor lities o ition, the cells ispl y strong SIg.