Advances in the pathological diagnosis of lymphomas

Lymphomas are common malignancies arising in the cervical lymph nodes and in the nasopharyngeal mucosa. Diagnosis of lymphoma remains in the domain of histopathology as fine needle aspiration biopsy is of limited value in this respect. Thanks to progress in our understanding of the structure and function of lymphoid tissue the classification of lymphomas is constantly changing. In addition the development of new therapeutic modalities forces pathologists to introduce new diagnostic methods including immunohistochemistry, flow cytometry and molecular biology techniques. The application of immunohistochemistry and cytometry is already well established in many diagnostic institutions. However, molecular biology techniques are considered to be difficult and expensive and, therefore, are not so wildly applied in routine diagnosis. One solution to this limitation is due to the development of relatively simple fluorescence and chromogen in situ hybridization methods. While application of these techniques is expensive, modern diagnostic methods for lymphoma represent only a small cost, relative to the costs involved in treatments such as chemotherapy or immunotherapy. Application of the above-mentioned techniques is absolutely necessary to fulfil the criteria of diagnosis of lymphomas introduced by the World Health Organization [1]. In this article, we describe some of the most important methods recommended for the diagnosis of lymphomas. It is necessary to note that the success of these methods requires the cooperation of clinicians and pathologists. The minimum requirements for the clinician include the fixation of the whole lymph node in 10% buffered formalin, which should be accompanied by a summary of clinical data. The minimum requirements for the pathologist include a knowledge of current diagnostic criteria and of the clinical setting. It must also be stressed that incorrect pathological diagnosis of lymphomas is sometimes due to unsatisfactory diagnostic techniques.