Pitfalls in the diagnosis of haematological malignancies

Increased knowledge of the immunophenotypic, cytogenetic and molecular heterogeneity of haematological diseases has challenged the traditional approach to disease classification based on morphology. In the current WHO classification, an integrated approach combining clinical details, morphology, immunophenotyping and genetic features is used for the diagnosis of haematological malignancies. An accurate diagnosis is essential for proper management of patients; moreover, there are novel drugs available which are designed to specifically target the underlying pathological abnormalities responsible for the development of the tumour. However, the risk of diagnostic errors remains high in diagnostic haematology and the main reason for this is lack of resources and expertise in small centres. There is a need for access to sub-specilaised haematology services, to ensure access to specialist expertise and a full range of testing beyond traditional stains. In this review a range of potential pitfalls in the diagnosis of haematological malignancies is outlined, arising at all stages from specimen collection to reporting. Knowledge of such pitfalls, some of which are common while others are rare but of vital clinical importance, helps in avoiding potential sources of errors. Insight into the technical details has been provided which helps to avoid the errors related to sampling and processing of specimens. The final diagnosis of haematological malignancies should be based upon a combination of clinical details, good technical preparation, access to diagnostic resources, good communication and in depth knowledge and experience of the haematopathologist.