Congenital acute T lymphoblastic leukaemia: report of a case with immunohistochemical and molecular characterisation

A newborn infant with congenital T cell lymphoblastic leukaemia presented w ith hepatosplenomegaly and pancytopenia at birth and died on the 21st day o f multi-organ failure. Biopsy and necropsy examination showed extensive aty pical lymphoid infiltrates in the lungs, Liver, spleen, kidneys, lymph node s, and bone marrow. Immunohistochemically, the lymphoid cells were TdT+, CD 3+, CD45RO+, and CD10-, CD79a-, CD20-. Genotypic analysis using polymerase chain reaction showed T cell receptor gamma chain gene rearrangement and ab sence of immunoglobulin heavy chain gene rearrangement. This appears to be the first documented case of congenital T cell lymphoblastic leukaemia. The case had unusual histological and immunogenotypic features, disseminated e arly, and pursued a highly aggressive course. Consideration of the diagnosi s is of paramount importance. The immunophenotypic studies and molecular ch aracterisation of such congenital leukaemias are critical in arriving at a definite diagnosis.