Introduction:
The
MLL gene (Mixed Lineage Leukaemia gene) is a positive regulator of the HOX gene
which is required for normal haemopoiesis. Alterations in this gene
favour leukemic maturation in either the myeloid or lymphoid lineage. MLL
rearranged acute lymphoblastic leukaemia is usually a disease of infants <12
months of age and is a relatively rare haematological malignancy in adults. It
may also present as a therapy related acute leukaemia, usually with myeloid
lineage.
Clinical
presentation:
Patient
MO was a 40 year old female who presented with neurological symptoms arising
from leukostasis. Leucophoresis was performed over 4 days to reduce her
white cell count (WCC) to normal levels and to minimise the risk of tumour
lysis syndrome with the commencement of induction chemotherapy. Despite several
courses of aggressive chemotherapy, she has only achieved a brief 3 month
remission.
Results:
The
full blood count on presentation showed a WCC of 359.4 x 109 /L, of
which 251.6 x 109/L were blasts with morphological features of
L2 blasts of the FAB classification. D-Dimer was moderately raised at 13.3
ug/ml FEU. Flow cytometry results were consistent with an early -B
lymphoid phenotype (CD19 +ve, CD79 weak +ve, CD34+ve, HLA DR +ve, TDT +ve,
CD10-ve), and variable CD15+ve was suggestive of rearranged MLL.
Dual –colour breakapart FISH probes demonstrated the MLL fusion in
84% of interphase cells examined. The karyotype at diagnosis was 46XX, t(4;11)
(q21;q23) karyotype and an additional isochromosome 7 at 5 months post
diagnosis.
Conclusion:
This
case of adult B -ALL with 11q23 rearrangement highlights its notorious disease
course and poor prognosis, featuring resistance to chemotherapy and difficulty
in achieving complete remission