Malignancy-like subtle histological changes and misdiagnosis pitfalls in reactive hyperplastic lymph nodes

Abstract

Faced with an enlarged lymph node, many pathologists are puzzled by the question of whether it is benign or malignant. Our practical experience has shown that alone histological knowledge of the lymph node is not sufficient to diagnose their pathology. Recognizing the extremely subtle histological changes of reactive lymph nodes is decisive in the indication of other complementary research methods, such as immunohistochemistry and possibly molecular biology, to distinguish between benign and malignant lymph nodes. Immunostaining is also essential to detect the misdiagnosis pitfalls that often emerge in benign reactive proliferative lymph nodes. This review summarizes malignancy-like subtle histological changes of reactive enlarged lymph nodes, the misdiagnosis pitfalls, and experience in using several immunohistochemical markers to distinguish these pitfalls.