Fluorescent In-Situ Hybridization is the Hand Mirror of Cytogenetics: A Rare Case of Near Tetraploidy in Pediatric Acute Lymphoblastic Leukemia

Identification of specific chromosomal changes has important prognostic and biological implications in childhood Acute Lymphoblastic Leukemia (ALL). ALL cases with >90 chromosomes are rare. Here, we report a case of near-tetraploidy in a 4 year old boy diagnosed with B-cell ALL, where the ploidy was identified by Fluorescent In- Situ Hybridization (FISH) and confirmed by Conventional Cytogenetics. Our aim was to enumerate multiple signals observed by FISH, and to confirm the same by cytogenetics. FISH on cytogenetically fixed air-dried slides was performed by using BCR/ABL and MLL probe .Two hundred cells were scored. BMA was cultured and G-banded metaphases were analyzed in accordance with ISCN 2013. The results of the FISH test showed more than two signals and cytogenetics revealed clones of near-tetraploidy with mn >90, karyotype: 90-92, XXY,-Y,-10,-10,-13, +14, +17, along with normal clones. The tetraploidy condition compared to hyperdiploid ALL has a poorer prognosis and the rarity of these cases makes accounting on treatment decisions a supposition. Presently, the patient is on standard treatment for ALL (UK ALL regime A). The numerical abnormality detected by FISH was confirmed by cytogenetics, which facilitated in reporting the results of this case earlier than the defined turnaround time. Therefore author opines that FISH reports should also contain observed additional information along with positive or negative status of the requested test.