Page 483 - Clinical Hematology_ Theory _ Procedures ( PDFDrive )

CHAPTER 23 ■ Myeloproliferative Neoplasms 467

Clinical Signs and Symptoms

T ro botic or blee ing proble s re the ost co only

seen isor ers in p tients with thro bocythe i . P tients

typic lly ni est e sy bruising, noseblee s, or g strointes-

tin l blee ing.

Spleno eg ly is oun in less th n h l o p tients.

Neurologic l ni est tions, however, re requent n

re c use by obstruction o the cerebr l icrov scul ture.

Cerebr l ische i n igit l ische i or even g ngrene

relent or respon co pletely to re uction o pl telet levels.

In ition, unexpl ine he to s re co on.

A benign or ree o he orrh gic or thro botic presen- FIGURE 23.12 Bone rrow biopsy o essenti l thro bocythe i

t tion c n be observe in subset o p tients ge ro 15 with eg k ryocytic hyperpl si . T e eg k ryocytes re cluster-

to 25 ye rs. ing n show ch r cteristic orphology: l rge size n hyperlo-
b te nuclei. (Reprinte ro McCl tchey KD. Clinical Laboratory

Laboratory Findings Medicine, 2n e , Phil elphi , PA: Lippincott Willi s & Wilkins,
2002, with per ission.)

Cellular Abnorm alities

T e cl ssic l bor tory f n ing in essenti l thro bocythe i Relationship of Thrombocythemia and PRV

is signif c ntly elev te peripher l bloo pl telet count.

T e nu ber o pl telets in the circul ting bloo is usu lly T e se in l events responsible or initi ting thro bocythe-

in excess o 1,000 × 10 /L, with ini u o 600 × 10 /L. i n PRV clones re unknown. Both clon l isor ers re
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Pl telet orphology reve ls nor l iscoi -sh pe cell; rke by low-gr e hyperproli er tion o two co itte

blee ing ti e is nor l. In ition, pseu ohyperk le i ste cell lines plus signif c nt sti ul tion o thir cell

y result uring the prep r tion o seru . Pot ssiu ro line. T ese two isor ers re i erenti te by single ch r-

pl telets is not rele se uring the ggreg tion ph se but cteristic—the bsence o n exp n e re bloo cell ss

uring the egr nul tion ph se o the co gul tion process. in thro bocythe i .

Peripher l bloo erythrocytes re requently hypochro- T e ut nt ste cell in both isor ers h s pre ispo-

ic n icrocytic. I splenic trophy is present, bnor l sition to un ergo tr ns or tion to either yelof brosis or

erythrocyte orphology inclu es t rget cells, Howell-Jolly cute leuke i . T e si il rities in the n tur l history o

bo ies, nucle te erythrocytes, n c nthocytes. T e tot l these MPNs suggest th t they both begin s very si il r, plu-

concentr tion o leukocytes is elev te in bout 50% o ripotent ste cell isor ers expresse i erently only t the

p tients but sel o excee s 40 × 10 /L. T e LAP v lue is colony- or ing cell level.
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nor l or incre se . Concentr tions o vit in B n uric
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ci re usu lly incre se . Treatment

Platelet Function T e course o the ise se is r ther benign n rese bles th t

In p tients with thro bocythe i , the e n extent o ggre- o PRV. It y evolve into nother or o MPN n in so e

g tion in uce by epinephrine, coll gen, or ADP is signif - c ses into cute leuke i .

c ntly lower th n in nor l controls. In ore th n h l o He pheresis h s been use in v riety o clinic l st tes,

p tients with thro bocythe i , the pl telet-rich pl s pri rily or its bility to re ove n o en ing co ponent,

oes not respon to epinephrine. T e tot l c lciu content likely to be either pl s or cellul r ele ents. T er peutic

o pl telets is lso signif c ntly lower. he pheresis is use ul in cert in clinic l con itions, but
ju icious pplic tion shoul be consi ere .

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Bone Marrow Alkyl ting gents n r io ctive phosphorous ( P) re

Bone rrow orphology in essenti l thro bocythe i e ective tre t ents, but these gents re ssoci te with n

(Fig. 23.12) is si il r to the rchitecture seen in PRV n incre se risk o leuke i n other neopl s s.

CML with ssoci te extre e thro bocytosis. However, sig- Although tre t ent o the sy pto tic p tient with pl te-

nif c nt i erences re observ ble between the rrow f n - let-lowering gents or ntipl telet rugs y be in ic te n

ings in MPN n those in extre e re ctive thro bocytosis. e ective, the role o ther py in the sy pto tic in ivi u l

Tese i erences inclu e the nu bers o eg k ryocytes, re ins highly controversi l. No re rk ble v nces h ve

the presence or bsence o eg k ryocyte clusters, st in ble been e in the tre t ent o MPNs except or the evelop-

iron, cellul rity, n reticulin content. ent o n ntipl telet rug, n greli e. T is gent see s to

In ition to incre se rrow cellul rity (hyperpl si ), be highly e ective in controlling thro bocytosis. T e rel tive

eg k ryocytic hyperpl si is striking. T is conspicuous erit o this gent co p re with inter eron lph n the

eg k ryocytic proli er tion lso ni ests polyploi y o i p ct o this gent on the surviv l ti e n on the qu lity o

the nuclei, gi nt or s, n clusters. li e o p tients with MPNs h ve yet to be ef ne .