PAX5 and leukemia: The patient was referred to the reference service in oncohematology tumors, therefor continued investigation with immunohistochemistry confirmed the diagnosis of B-LBL/leukemia, presenting positivity for markers of lymphoid B precursor cell antigens (TdT, marker present in hematopoietic progenitor cells; PAX5, marker present in B lymphocytes in all stages of maturation) and subsequently progressed with pancytopenia.