Infantile Acute Monoblastic Leukemia with MLL Gene Rearrangements

A 7 month infant presented with fever and breathlessness with raised total counts. Examination revealed 90 % blasts with prominent nucleoli. Flow cytometry revealed a tight cluster in the monocytic region. The blasts showed homogenous bright CD 33/4/64/HLA D with heterogeneous expression of CD14/15/11c. Blasts were negative for CD13/MPO/Cytoplasmic CD3/19/7/34/117/5/22/TdT/CD 61/41. FISH revealed MLL gene rearrangements in the blasts. No evidence of Down's syndrome on cytogenetic studies was noted. Diagnosis of Infantile acute monoblastic leukemia was made. These leukemias are rare in infants and are associated with a poor outcome.