APPLICATION OF THE POLYMERASE CHAIN-REACTION FOR THE DIAGNOSIS OF MALIGNANT-LYMPHOMA OF THE NASAL AND ORAL CAVITIES

Difficulties are often encountered in the diagnosis of malignant lymph oma of the oral and nasal cavities by histology and immunohistochemist ry because these malignancies may be complicated by inflammation and n ecrosis. In the present study, immunoglobulin heavy chain (IgH) and T- cell receptor (TCR) gene rearrangements were examined by the polymeras e chain reaction (PCR) in formalin-fixed and paraffin-embedded specime ns obtained from 18 patients; the advantages of this method were evalu ated. Twelve of these patients were diagnosed as having malignant lymp homa and six had tumors highly suggestive of malignant lymphoma. Fourt een (78%) of the Is cases were diagnosed as malignant lymphoma histolo gically and immunohistochemically. Sixteen (89%) of the 18 cases were shown to be monoclonal by PCR. The four cases that could not be histol ogically or immunohistochemically diagnosed as malignant lymphoma show ed monoclonal gene rearrangement by PCR. As a result, six patients sus pected of having a malignant lymphoma were diagnosed as having one. Th e diagnosis of malignant lymphoma by PCR alone still has various probl ems. However, when the results of PCR are evaluated together with hist opathological and immunohistochemical results, PCR makes a useful cont ribution to the diagnosis of malignant lymphomas of the nasal and oral cavities.