Discussion
Because of genetic features and clinical characteristics infant
leukemias are different from other childhood leukemias. Median duration
of event free survival is 11 months(4). It is well known that
hyperleukocytosis and MLL rearrangement in infant leukemia are
associated with poor prognosis (1). Unlike these features of infant
leukemias this patient didn’t presented with hyperleukoctosis and she
hadn’t MLL rearrangement. In this case who had a good prednisolone
response, t (5; 15) (p15;q11.2) was detected in cytogenetic analysis.
t(5; 15) was first reported in three infant ALL in 1987 (4,8). Seven
infant ALL and only two childhood ALL patients with t (5; 15) (p15;
q11-13) was reported until 2014 (6,9,10). On the basis of these data it
was speculated that this chromosomal abnormality was characteristics of
infant ALL and related with good prognosis(6).
Although CD10 weak positivity (6) is noteworthy in cases with t(5; 15)
complete remission was achieved with induction therapy. Also event free
survival of cases with t (5; 15) was better than those with MLL
rearrangement (9). On the other hand 45-month-old girl reported by Kwon
et al. had a good prednisolon response and achieved complete remission
with induction therapy (10).
The 21-month-old boy reported by Lee et al. achieved remission 3 months
after start of chemotherapy. However, Lee et al. reported that t (5; 15)
was detected in cytogenetic analysis during relapse and they stated that
it would be find positive at diagnosis if cytogenetic analysis was
performed (9). If it can be detected before morphological relapse, it
will be useful for the follow-up of patients. However infant leukemias
with t(5; 15) and their clinical outcomes need to be reported.
On the other hand while hyperleukocytosis was detected in two of the
cases, other two cases were not known. The remaining patients with t(5;
15) did not have hyperleukocytosis reported so far (6,9,10), like our
patient. Extramedullary infiltration was reported only one of these
patients. We thought that renal enlargement was related with
extramedullary infiltration because her kidney shrunk in normal size
with induction therapy.
Translocations such as t(9:22), t(1; 19), t(12; 21) known to be
associated with leukemias and can be detected using RT-PCR and FISH. But
cytogentic analysis still significant at the time of leukemia diagnosis.
If we didn’t perform cytogenetic analysis on bone marrow sample at
diagnosis we couldn’t catch t(5;15) in this case. On the other hand
cytogenetic analysis not always available. For instance Heerema and et
al who reported first three infant ALL cases with t(5;15) could obtain
39 cytogenetic analyses of 100 infant ALL in their study (4).
In addition, our patient had an ectrodactyly on her right hand (Figure
1). Split-hand / split-foot malformation (SHFM) defined ectrodactyly is
seen once in 90,000 live births. Although it shows autosomal dominant
inheritance autosomal recessive inheritenace has been reported. It is
generally sporadic but it may be familial. There are syndactyly and
aplasia in the phalanges with midline cleft in hand. There was no
ectrodactyly in our patient’s family member. SHFM is a heterogeneous
condition caused by genetic abnormalities. Thus classified according to
genetic defect and association with cleft palate-lip anomaly, hearing
loss and fallot tetralogy (12-14). Our patient had ’isolated’
ectrodactyly. Besides, ALL cases with t(5; 15) with ectrodactyly have
not been reported yet.
Among the childhood malignancies, congenital anomalies are most common
in leukemias. These anomalies include cleft palate, spina bifida, rib
anomalies and birthmarks(15). It is suggested that rib anomalies may be
associated with childhood leukemias (16). However the relationship
between a specific congenital anomaly and leukemias is not known except
Down Syndrome. Those with congenital anomalies were reported to have
more cancer diagnoses in infancy than those without(17).
In conclusion, the case of infant leukemia reported here is the first
case who had ectrodactyly with t (5:15). We consider that the clinical
features, response to treatment and concomitant congenital anomaly of
this case contribute to knowledge about infant leukemias.
Authors have no conflict of interest to declare.
ETHICS STATEMENT: Parents of patient have permitted with signature to
publish their children’s photos.