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Chapter 15 Myeloproliferative neoplasms / 211

Primary myelofibrosis and CML are responsible Treatment
for most cases of massive ( > 20 cm) splenic enlarge-

This is usually palliative and aimed at reducing the
ment in the UK and North America (see Table

effects of anaemia and splenomegaly. Blood transfu-
10.1 ).
sions and regular folic acid therapy are used in
severely anaemic patients. Hydroxyurea may help to
reduce splenomegaly and hypermetabolic symp-
Laboratory fi ndings

toms. Trials of thalidomide, lenalidomide, azacyti-

1 Anaemia is usual but a normal or increased dine and histone deacetylase inhibitors are in
haemoglobin level may be found in some progress. JAK2 inhibitors (in clinical trials) reduce

patients. spleen size, and can be effective in both JAK2
2 The white cell and platelet counts are frequently mutated and wild - type cases. Danazol, an androgen

high at the time of presentation. Later in the derivative, may improve anaemia in approximately
disease leucopenia and thrombocytopenia are 30% of patients. Erythropoietin can also be tried
common. but may cause splenic enlargement.
3 A leucoerythroblastic blood film is found. Th e Splenectomy is considered for patients with

red cells show characteristic ‘ tear - drop ’ poikilo- severe symptomatic splenomegaly – mechanical dis-
cytes (Fig. 15.9 ). comfort, thrombocytopenia, portal hypertension,

4 Bone marrow is usually unobtainable by aspira- excessive transfusion requirements or hypermeta-
tion. Trephine biopsy (Fig. 15.6 b) shows a bolic symptoms. Splenic irradiation is an alternative
fibrotic hypercellular marrow. Increased meg- but usually provides relief only for 3 – 6 months.

akaryocytes are frequently seen. In 10% of cases Allopurinol is indicated in virtually all patients to
there is increased bone formation with increased prevent gout and urate nephropathy from hyperu-
bone density on X - ray. ricaemia. Allogeneic stem cell transplantation may
5 JAK2 kinase is mutated in approximately 50% of be curative for young patients.

cases. The median survival is less than 5 years and
6 High serum urate and LDH levels refl ect the causes of death include heart failure, infection and
increased but largely ineffective turnover of hae- leukaemic transformation. A haemoglobin level of

mopoietic cells. < 10 g/dL, a white cell count of less than 4 or greater
9
7 Transformation to acute myeloid leukaemia than 30 × 10 /L and the presence of abnormal chro-
occurs in 10 – 20% of patients. mosomes are associated with a worse prognosis.

Figure 15.9 Peripheral blood fi lm
in primary myelofi brosis.
Leucoerythroblastic change with
‘ tear - drop ’ cells and an
erythroblast.