Diagnosing certain diseases often relies on identifying specific cellular markers. Reed-Sternberg cells are one such marker, recognized for their distinctive appearance. Their unusual morphology sets them apart from other cells observed in diseased tissues, making them a key subject of study in pathology.
Defining Reed-Sternberg Cells
Reed-Sternberg cells are abnormally large, typically 15 to 45 micrometers in diameter. They are characterized by abundant cytoplasm, which can appear slightly basophilic or amphophilic. A defining feature is their nuclear structure, often presenting with at least two nuclear lobes or multiple distinct nuclei.
These cells frequently exhibit prominent nucleoli, which are large and eosinophilic, meaning they stain pink or red with certain dyes. This appearance, sometimes described as “owl’s eye” due to two prominent nucleoli with a clear area around them, is a classic identifying characteristic. Reed-Sternberg cells generally originate from abnormal B-lymphocytes, specifically germinal center B-cells that have evaded programmed cell death.
Their Unique Link to Hodgkin Lymphoma
The presence of Reed-Sternberg cells is a hallmark of classical Hodgkin lymphoma. These cells are rarely found in other conditions, making their identification significant for distinguishing Hodgkin lymphoma from other cancers, including non-Hodgkin lymphomas. While malignant, they typically constitute only a small fraction, often less than 1% to 5%, of cells within the affected tissue.
The surrounding tissue usually contains a diverse population of non-malignant immune cells, such as T-cells, B-cells, eosinophils, macrophages, and plasma cells. This inflammatory background is characteristic of Hodgkin lymphoma, where Reed-Sternberg cells interact with their microenvironment.
Identifying Reed-Sternberg Cells
Pathologists primarily identify Reed-Sternberg cells through microscopic examination of tissue biopsies, most commonly from lymph nodes. An excisional biopsy, which involves removing an entire lymph node, is generally preferred to ensure sufficient tissue for diagnosis. Initial observations under a light microscope reveal their large size, multi-lobed nuclei, and prominent nucleoli.
To confirm their identity, specialized staining techniques are employed, particularly immunohistochemistry. This method uses antibodies to detect specific proteins on the cell surface. Reed-Sternberg cells typically show positive staining for CD30 and CD15 markers. While CD30 is consistently expressed, CD15 positivity is observed in about 80% of classical Hodgkin lymphoma cases. These specific markers help differentiate Reed-Sternberg cells from other atypical cells that might resemble them.
Significance in Diagnosis and Treatment
The identification of Reed-Sternberg cells is fundamental for a definitive diagnosis of classical Hodgkin lymphoma. Their presence is a necessary criterion for this diagnosis. This precise diagnosis is crucial because Hodgkin lymphoma often responds favorably to specific treatment protocols that differ from those used for other lymphomas.
Treatment plans for Hodgkin lymphoma commonly involve combination chemotherapy regimens, such as ABVD (doxorubicin, bleomycin, vinblastine, and dacarbazine), sometimes combined with radiation therapy. While their presence is diagnostic, understanding these cells allows for tailored therapeutic approaches, contributing to the high cure rates often seen in Hodgkin lymphoma.