Identification of large cell undifferentiated tumours in lymph nodes using leucocyte common and keratin antibodies.

A total of 43 cases undifferentiated large cell tumours presenting in lymph nodes were stained by immunoperoxidase techniques using antibodies against keratin and a leucocyte-associated glycoprotein. In 26 cases diagnosed histologically as metastatic carcinoma, staining with the keratin antibody suggested a squamous cell origin in 11 cases. This was supported by microscopic observation of intracellular filaments in seven cases. In 15 patients in whom the original diagnosis was uncertain, a definite diagnosis was possible in all cases following immunoperoxidase staining with the two antibodies and most of these proved to be large cell lymphomas. In two cases a potentially major diagnostic error was detected. It is suggested that the staining of undifferentiated human neoplasms using combinations of antibodies reactive with epithelial and lymphoid cells should result in much greater diagnostic accuracy in the field of large cell tumours presenting in lymph nodes.