Reed sternberg cells are found in

* Reed-Sternberg cells * They are usually derived from B lymphocytes, classically considered crippled germinal center B cells. * Seen against a sea of B cells, they give the tissue a moth-eaten appearance. * They are named after Dorothy Reed Mendenhall and Carl Sternberg, who provided the first definitive microscopic descriptions of Hodgkin&;s disease. * Reed-Sternberg cells are large and are either multinucleated or have a bibbed nucleus (thus resembling an "owl&;s eye" appearance) with prominent eosinophilic inclusion-like nucleoli. * Reed-Sternberg cells are CD30 and CD15 positive, usually negative for CD20 and CD45. * The presence of these cells is necessary in the diagnosis of Hodgkin&;s lymphoma - the absence of Reed-Sternberg cells has very high negative predictive value. * They can also be found in reactive lymphadenopathy (such as infectious mononucleosis, carbamazepine associated lymphadenopathy) and very often in other types of non-Hodgkin lymphomas. * A special type of Reed-Sternberg cells is the lacunar histiocyte, whose cytoplasm retracts when fixed in formalin, so the nuclei give the appearance of cells that lie with empty spaces (called lacunae) between them. These are characteristic of the nodular sclerosis subtype of Hodgkin&;s lymphoma REF : HARRISONS 21ST ED