The diagnosis of hematologic diseases has traditionally been based on features of peripheral blood and bone marrow (BM) cytology. Histologic examination of the BM has been used for the staging of neoplasias when aspiration is not possible due to fibrosis. Cytology permits a better evaluation of cell morphology and a quantitative analysis of the different BM lineages. Histology shows the BM structure, topology of cells and the microenvironment, besides identifying pathologic structures such as granulomas, fibrosis, and metastases. More recently, several new technologies have been developed, and the pathophysiology of diseases has been better elucidated. The WHO classification of hematologic malignancies describes entities based on morphology, phenotype, and in many cases, cytogenetic and molecular features. This has made targeted therapy feasible. Therefore, there is need to confirm the diagnosis using data from different techniques. Some methods are also useful to quantify residual disease after treatment, and confirm cure. Thus, several kinds of remission have been defined, such as " hematologic" , " phenotypic" , " cytogenetic" and " molecular" remission. In benign diseases, presenting with cytopenias other than anemia, BM examination is useful together with biochemical and serological tests.
Cytology; histology; diagnosis; hematologic disorders; WHO classification
