The Value of Immunocytochemistry in Differentiating High-Grade: Lymphoma from Other Anaplastic Tumours: A study of anaplastic tumours from 1940 to 1960.

Immunocytochemistry is now established in many histology laboratories for diagnostic purposes and is routinely used in ascribing an origin to poorly differentiated tumours. This raises the question of whether traditional morphological skills are being abandoned in favour of new technology and, if so, whether that is justified. Twenty-three lymph node biopsies diagnosed as anaplastic carcinoma, reticulosarcoma or unclassifiable tumour between 1940 and 1960 (when immunocytochemistry was not available) were retrieved from the archives of the Radcliffe Infirmary. Paraffin sections were stained with a panel of monoclonal antibodies previously shown to be useful in the identification of tumours of uncertain origin. Of the 15 cases given a definite morphological diagnosis six (40%) were shown to be incorrect on the basis of immunostaining. In the eight remaining cases in which no diagnosis was recorded immunostaining provided a clear diagnosis in seven instances. These results are similar to those recorded on contemporary cases and demonstrate the value of immunocytochemical staining, as an adjunct to traditional morphological examination. In addition, it is clear that currently available monoclonal antibodies are suitable for use on routinely processed material more than 30 years old.