The Basophil Dilemma

Case Report

Ann Hematol Oncol. 2017; 4(2): 1137.

The Basophil Dilemma

Sidhwa K¹, Mansukhani D¹, Padate B², Gupta S² and Khodaiji S¹*

¹Department of Hematopathology, Laboratory Medicine, Hinduja National Hospital & Medical Research Centre, India

²Department of Hematology, Hemato-oncology and BMT, Hinduja National Hospital & Medical Research Centre, India

*Corresponding author: Khodaiji S, Department of Hematopathology, Laboratory Medicine, P.D, Hinduja National Hospital & Medical Research Centre, Veer Savarkar Marg, Mahim, Mumbai - 400016, India

Received: January 09, 2017; Accepted: February 25, 2017; Published: February 28, 2017

Abstract

Acute Myeloid Leukemia (AML) with basophilic differentiation i.e., Acute Basophilic Leukemia (ABL) and Chronic Myeloid Leukemia (CML) in basophilic blast crisis are two entities which are characterized by the primary differentiation into basophilic lineage as ascertained by electron microscopy, special stains and/or immunophenotyping. We report a case where we were faced with a dilemma of differentiating between these two entities on morphology.

The patient was a 60 year oldwoman who showed an excess of blasts with basophilic differentiation on peripheral blood and bone marrow at presentation. There was no previous history of a hematological malignancy. The Philadelphia (Ph) chromosome was positive on fluorescence in-situ hybridization (FISH). However Ph chromosome positivity has also been noted in ABL cases, further adding to the difficulty in diagnosis.

Keywords: Acute myeloid leukemia; Chronic myeloid leukemia; Philadelphia chromosome; Acute basophilic leukemia; Basophilic blast; Immunophenotyping

Introduction

Acute basophilic leukemia and basophilic blast crisis in CML are very rare diseases with only few reported cases. Differentiating between these two conditions can be very challenging due to overlapping morphology and immunophenotypic features. Further, established protocols or guidelines to distinguish these two entities are not readily available in literature. This distinction however is imperativein order tomake therapeutic decisions. Incidence of Ph positive AML appears to be very low, apparently constituting less than 1% of allnewly diagnosed cases of AML [1,2]. In a report of 8 cases of ABL by Peterson, et al. 3 were Ph chromosome positive [t(9;22)], without showing clinical features of CML, while no other chromosomal abnormality was found in the rest, including t(6;9) which is the abnormality commonly seen in AML patients with basophilia [3].

Generally, presence of Phchromosome,provides strong evidence for blast crisis arising in the background of CML [4]. However, Peterson, et al. have observed thatPh chromosome positivity can also be seen in ABL cases, thus adding to the difficulty in diagnosis [5]. We report a case illustrative of a diagnostic dilemma of ABL versus a CML in basophilic blast crisis.

Case Presentation

A 60-year-old female presented with a short, 10 days history of loss of appetite and generalized weakness. Physical examination of the patient revealed a massive splenomegaly. A complete hemogram showed a WBC of 136X109/L, Hemoglobin of 93 g/L and a platelet count of 155X109/L.

The peripheral blood smear showed a differential count comprising 9% blasts, 1% promyelocyte, 12% myelocytes, 9% metamyelocytes, 16% neutrophils, 3% lymphocytes, 6% monocytes, 41% basophils and 3% eosinophils. The blasts were large, showing basophilic cytoplasm, high N:C ratio and open chromatin. In addition a population of cells, interim in size between blasts and mature basophils was seen. These cells showed presence of few basophilic granules and were difficult to identify as they had overlapping features between basophilic blasts and basophilic promyelocytes/ myelocytes (Figure 1).