Reed-Sternberg cells represent a distinct type of abnormal cell, characterized by their unique appearance under a microscope. Their presence holds particular significance in understanding certain medical conditions.
What Are Reed-Sternberg Cells?
Reed-Sternberg cells are unusually large, abnormal lymphocytes. These cells typically measure between 30 and 50 microns, considerably larger than normal lymphocytes. A defining characteristic is their appearance under a microscope, often described as resembling an “owl’s eye” due to prominent, eosinophilic nucleoli and either multiple nuclei or a single bilobed nucleus. The nuclei can also be multilobated.
These cells originate from B lymphocytes, specifically from germinal center or post-germinal center B cells. While they retain the genetic signature of B cells, Reed-Sternberg cells in classical Hodgkin lymphoma often fail to express many B-cell specific genes. This leads to their unique morphology and behavior within tissues.
Their Connection to Hodgkin Lymphoma
Reed-Sternberg cells are the hallmark pathological finding for classical Hodgkin lymphoma, a cancer affecting the lymphatic system. Their presence is a necessary criterion for diagnosing classical Hodgkin lymphoma. These abnormal cells are the tumor cells of Hodgkin lymphoma, though they constitute only a small fraction, typically less than 1%, of the total cellular population in an affected lymph node or tissue.
Despite their sparse numbers, these cells are surrounded by a substantial number of reactive inflammatory cells, such as eosinophils, neutrophils, mature lymphocytes, plasma cells, and histiocytes. These surrounding cells are attracted by cytokines released by the Reed-Sternberg cells, which support their growth. This characteristic cellular environment, with the distinctive Reed-Sternberg cells amidst a reactive inflammatory background, is a key feature of classical Hodgkin lymphoma.
How Reed-Sternberg Cells Are Identified
Identification of Reed-Sternberg cells typically begins with a biopsy, often of an enlarged lymph node or affected tissue. The tissue sample is then prepared and examined under a microscope by a pathologist. The pathologist looks for the characteristic “owl’s eye” appearance and large size of these cells.
To confirm their identity and differentiate them from other similar cells, pathologists use special laboratory techniques, primarily immunohistochemistry (IHC). This method involves applying antibodies that bind to specific proteins on the cell surface. Reed-Sternberg cells in classical Hodgkin lymphoma usually test positive for markers, such as CD30 and CD15. The presence of both CD30 and CD15 staining is a strong indicator, as their co-expression is uncommon in other conditions.
Why Reed-Sternberg Cells Are Important for Diagnosis
The identification of Reed-Sternberg cells is important in guiding patient care because it allows for the precise classification of lymphoma. Their presence helps distinguish Hodgkin lymphoma from other types of lymphoma, particularly non-Hodgkin lymphomas, which require different treatment strategies. Correctly identifying the specific type of lymphoma directly impacts the choice of therapy, as Hodgkin lymphoma generally has a high cure rate and is sensitive to specific radiation and chemotherapy regimens.
While the presence of Reed-Sternberg cells is characteristic, a conclusive diagnosis also relies on evaluating the overall cellular environment within the biopsy sample and the patient’s clinical presentation. Reed-Sternberg-like cells can occasionally appear in other conditions or some non-Hodgkin lymphomas, making the complete pathological assessment, including the immunophenotype and surrounding cellular context, necessary for an accurate diagnosis. This comprehensive evaluation ensures patients receive the most appropriate and effective treatment plan.