We read case report on long term survival in aggressive NK cell leukemia
by Patel, et al. with great interest [1]. It is a very rare entity
in pediatric population [2-4]. Recently, we also managed a similar case in
an infant.
A 9-month old boy presented with recurrent respiratory
tract infections since 2 months, swelling of both eyes since 2 months,
bilateral testicular enlargement noticed since one month. At admission he
had pallor, bilateral proptosis, hepatosplenomegaly and bilateral
testicular enlargement. His complete blood counts showed pancytopenia
(hemoglobin-7.7g/dL, total leukocyte count-5000/cumm, platelet-100,000/cumm,
absolute neutrophil count-350/cumm). CT abdomen did not reveal any mass.
Bone marrow aspirate and biopsy showed presence of infiltration with MPO
negative malignant cells, which could not be further characterized
morphologically. Flow cytometry analysis failed to pick up the lineage of
the cells. Testicular biopsy revealed diffuse infiltration by a round cell
tumor with brisk mitotic activity. Tumor cells showed positive staining
with CD45RO, CD43, CD99 and CD56. These were focally positive for LCA.
Staining for CD3, CD20, CD10, MPO and ALK-1 was negative. It was opined to
be aggressive NK cell leukemia (ANKL). Bone marrow cytogenetics showed
trisomy of chromosome 8. FISH studies for MLL, BCR-ABL and TEL-AML were
negative. Cerebrospinal fluid (CSF) was negative for any blasts. He
received chemotherapy as per Interfant-99 protocol [5]. He was in clinical
remission (CR) on day 33 of induction. He relapsed in bone marrow and CSF
sixteen months from diagnosis during maintenance phase of therapy.
Diagnosing ANKL can be a challenge for the clinician,
pathologist and haematologist. Our patient did not respond well to
chemotherapy in contrast to report by Patel, et al. [1] although
initial response to therapy was good. Infants with MLL gene rearrangement
have poor prognosis [5], which was absent in our case. ANKL with bilateral
testicular mass and trisomy 8 in an infant has not been reported
previously. It is interesting to note that the outcome for the pediatric
patients reported in the literature is somewhat better than that of their
adult counterparts, with 7 of 13 children surviving at the time of last
follow-up (54%) [3]. Most children undergo stem cell transplant (SCT) as
salvage at relapse except one case who had SCT in CR1 and is alive at last
follow up [2]. ICE chemotherapy has been suggested to be more effective
for NK cell malignancy [3].
References
1. Patel AP, Ghatak SB, Patel JA. Long term survival in
aggressive NK-cell leukemia. Indian Pediatr. 2010;47:807-8.
2. Ohnuma K, Toyoda Y, Nishihira H, Iguchi A, Honda K,
Nagao T, et al. Aggressive natural killer (NK) cell lymphoma:
report of a pediatric case and review of the literature. Leuk Lymphoma.
1997;25:387-92.
3. Shaw PH, Cohn SL, Morgan ER, Kovarik P, Haut PR,
Kletzel M, et al. Natural killer cell lymphoma: report of two
pediatric cases, therapeutic options, and review of the literature.
Cancer. 2001;91: 642-6.
4. Petterson TE, Bosco AA, Cohn RJ. Aggressive natural
killer cell leukemia presenting with hemophagocytic lymphohistiocytosis.
Pediatr Blood Cancer. 2008;50:654-7.
5. Pieters R, Schrappe M, De Lorenzo P, Hann I, De
Rossi G, Felice M, et al. A treatment protocol for infants
younger than 1 year with acute lymphoblastic leukaemia (Interfant-99): an
observational study and a multicentre randomised trial. Lancet.
2007;370:240-50.