Vol 3, No 3 (2012)
Case report
Published online: 2012-10-11
Chronic myeloid leukemia as the second myeloproliferative neoplasm evolving after primary myelofibrosis
Hematologia 2012;3(3):271-279.
Abstract
Chronic myeloproliferative neoplasms (MPN) can be categorised into Philadelphia-negative
(Ph–) disorders and Philadelphia-positive (Ph+) chronic myeloid leukaemia (CML). Each of
these neoplasms presents specific clinical and laboratory symptoms however occasionally these
diseases may coexist together, thus making classification difficult when such syndromes overlap.
A case study is presented of just such an occurrence. This was a 44-year-old woman with
primary myelofibrosis (PMF) that had been recognised in 2004 according to obligatory WHO
criteria. After four years of follow-up the Ph chromosome appeared. Despite still having bone
marrow morphology characteristic of PMF, CML was found as shown by an atypical bone
marrow histology. A ten-month treatment with imatinib proved ineffective with complications
arising of profound anaemia thereby requiring dose reduction, withdrawing the drug and red
blood cell transfusion. It was only by administering nilotinib that the Ph+ clone was eradicated,
however at the same time some abnormal Ph- clones were observed showing numerous
mutations indicative of genetic instability. The clinical course and molecular biology results
then enabled recognition of two MPNs, namely PMF and CML, which had probably evolved
from two independent cell clones. This case therefore demonstrates that diagnosing MPN can
be challenging. The coexistence of two neoplasms should be taken into consideration in cases
presenting an unusual clinical course and overlapping molecular abnormalities. Cytogenetic
and molecular monitoring is thus important in such clinical cases. It allows not only a diagnosis
MPN, but also new cell clones can be identified that lead to another MPN emerging as shown
in this case report.
(Ph–) disorders and Philadelphia-positive (Ph+) chronic myeloid leukaemia (CML). Each of
these neoplasms presents specific clinical and laboratory symptoms however occasionally these
diseases may coexist together, thus making classification difficult when such syndromes overlap.
A case study is presented of just such an occurrence. This was a 44-year-old woman with
primary myelofibrosis (PMF) that had been recognised in 2004 according to obligatory WHO
criteria. After four years of follow-up the Ph chromosome appeared. Despite still having bone
marrow morphology characteristic of PMF, CML was found as shown by an atypical bone
marrow histology. A ten-month treatment with imatinib proved ineffective with complications
arising of profound anaemia thereby requiring dose reduction, withdrawing the drug and red
blood cell transfusion. It was only by administering nilotinib that the Ph+ clone was eradicated,
however at the same time some abnormal Ph- clones were observed showing numerous
mutations indicative of genetic instability. The clinical course and molecular biology results
then enabled recognition of two MPNs, namely PMF and CML, which had probably evolved
from two independent cell clones. This case therefore demonstrates that diagnosing MPN can
be challenging. The coexistence of two neoplasms should be taken into consideration in cases
presenting an unusual clinical course and overlapping molecular abnormalities. Cytogenetic
and molecular monitoring is thus important in such clinical cases. It allows not only a diagnosis
MPN, but also new cell clones can be identified that lead to another MPN emerging as shown
in this case report.
Keywords: chronic myeloproliferative neoplasmsprimary myelofibrosischronic myeloid leukemiagenetic instability
