Hypocellular acute leukemia: study of clinical and hematological features

Abstract

Hypocellular acute leukemia was previously referred to as smoldering leukemia. This is currently defined as having ≥20 % blasts in peripheral blood or bone marrow with cellularity of less than 20 % in bone marrow biopsy at presentation. Hypocellular variants of acute myeloid leukemia (AML) are commoner than that of acute lymphoid leukemia (ALL). They may pose a diagnostic challenge to the treating clinician and pathologist as they can simulate hypoplastic myelodysplastic syndrome and aplastic anemia. It is of utmost importance to distinguish these overlapping disorders as treatment modalities differ. Details of clinical features, complete blood counts, bone marrow aspirate findings, percentage cellularity, pattern of infiltration in trephine biopsies, and immunophenotyping by flow cytometry or immunohistochemistry were analyzed in cases diagnosed as hypocellular acute leukemia. Hypocellular acute leukemia constituted 2.5 % (8/316) of all diagnosed cases of acute leukemia during the study period. Seven of the eight cases of hypocellular acute leukemia were hypocellular AML while one was hypocellular ALL. Median age of patients was 45 years, with a male:female ratio of 1.7:1. Mean duration of symptoms was 1.2 months, with most common presenting feature being fever. None of the patients except one had an antecedent hematologic disorder or chemotherapy or radiotherapy. Hypocellular acute leukemia is important to recognize from other overlapping disorders. Clinical parameters and laboratory data including immunophenotyping can aid in distinguishing them.