INTRODUCTION
Leukemia is the most common childhood cancer, with T-cell acute
lymphoblastic leukemia (T-ALL) comprising 10-15% of pediatric leukemia
diagnoses1,2. T-ALL is an aggressive malignancy, with
a median age of diagnosis of 9 years old2. T-ALL is
rarely reported in children less than 12 months of age with only 2 cases
in the literature, neither of which outlined treatment, and both of
which were before routine use of nelarabine as upfront
therapy3,4. Later presentation in childhood is
hypothesized to occur due to genetic changes in T-ALL rarely arising in
utero and instead develop over time2. From the limited
information regarding infantile T-ALL, the genetic mutations ofNOTCH2, NOTCH3, PTEN, and KRAS have been
identified3. Activation of the ERK5 pathway was also
noted; this pathway is regulated by growth factors among other
stimuli3. The paucity of data regarding clinical
presentation, management, genomics, and outcomes of infantile T-ALL
results in difficult treatment decisions including potential use of
agents such as nelarabine, with overall uncertainty of disease course
and treatment toxicity.