The Lymph Node Biopsy

Abstract

Abstract Lymphadenopathy is an extremely common sign in clinical medicine which may accompany a wide variety of conditions. The diagnosis of the etiology of lymphadenopathy will not infrequently require biopsy of an enlarged lymph node for pathologic examination and study. Selection of patients requiring lymph node biopsy requires a good deal of clinical judgment. The significance of palpably enlarged lymph nodes ranges from the trivial (e.g., cervical lymph node enlargement accompanying an upper respiratory infection) to the life threatening (e.g., lymph node enlargement as a manifestation of acquired immunodeficiency syndrome [AIDS] or malignant lymphoma). Lymph node enlargement may be localized or generalized but will usually have been persistent and unexplained before lymph node biopsy is considered. The differential diagnosis of lymph node enlargement will vary with the age of the patient. Reactive lymphadenopathies are, in general, more common in childhood and young adulthood, whereas malignant neoplasms, both primary (i.e., malignant lymphoma) and secondary (i.e., metastatic carcinoma), are more common in adults. Similarly, clinical findings also affect the differential diagnosis. A lymph node which is tender to palpation and soft in consistency is most likely reactive, whereas a lymph node which is rock hard is most commonly maligant. The lymph nodes in malignant lymphoma typically have a firm or “rubbery” consistency on palpation. The size of the lymph nodes is also of significance. The largest lymph nodes are typically seen in neoplastic conditions, such as Hodgkin’s disease and non-Hodgkin’s lymphomas; however, striking lymph node enlargement may be seen in some reactive conditions, for example Rosai-Dorfman disease (sinus histiocytosis with massive lymphadenopathy). Similarly, lymph nodes which are only slightly enlarged may harbor malignant lymphoma, particularly if other suggestive clinical signs (i.e., hepato splenomegaly) are evident. Selection of patients for lymph node biopsy therefore requires consideration of all the clinical signs and symptoms. Laboratory evaluation may also be helpful prior to lymph node biopsy.