Which of the following immunohistochemical stains is used for the diagnosis of lymphomas –
**Core Concept**
Immunohistochemical staining is a diagnostic tool used to identify specific proteins or antigens in tissue samples, aiding in the diagnosis of various conditions, including lymphomas. This technique relies on the use of monoclonal antibodies that bind to specific antigens, allowing for the visualization of these antigens under a microscope.
**Why the Correct Answer is Right**
The diagnosis of lymphomas often involves the use of immunohistochemical stains to identify specific cell surface markers or proteins. For instance, the CD20 antigen is commonly expressed on B-cell lymphocytes, making CD20 immunostaining a valuable tool for identifying B-cell lymphomas. This antigen is recognized by the monoclonal antibody L26, which is used in the immunohistochemical staining process.
**Why Each Wrong Option is Incorrect**
* **Option A:** This option is incorrect as it does not specify a commonly used immunohistochemical stain for lymphoma diagnosis. While immunoglobulin stains may be used, they are not as specific for lymphoma diagnosis as CD20 staining.
* **Option B:** This option is incorrect as it is not a commonly used immunohistochemical stain for lymphoma diagnosis. Although it may be used in other contexts, it is not a standard marker for lymphoma identification.
* **Option C:** This option is incorrect as it is not a specific immunohistochemical stain for lymphoma diagnosis. While certain markers may be used to identify specific subtypes of lymphoma, this option does not specify a commonly used stain.
**Clinical Pearl / High-Yield Fact**
CD20 immunostaining is a valuable diagnostic tool for identifying B-cell lymphomas, and it is commonly used in conjunction with other markers to aid in diagnosis. A key point to remember is that CD20 is not expressed on plasma cells, making it a useful marker for distinguishing between B-cell lymphomas and plasma cell neoplasms.
**Correct Answer: C. CD20**