Therapy-relevant discrepancies between diagnoses of institutional pathologists and experienced hematopathologists in the diagnosis of malignant lymphoma.

We have studied therapy-relevant discrepancies in the diagnoses of institutional pathologists and a panel of 4 experienced hematopathologists in 375 cases from patients with malignant lymphoma. Two hundred and fifty four cases (68%) were contributed by non-panel pathologists and 121 (32%) by individual panel pathologists. Overall, in 24% (91/375) of the cases, therapy-relevant discrepancies were present between institutional pathologists and panel diagnoses. Thirty-four percent (87/254) therapy-relevant discrepancies were present in cases contributed by non-panel pathologists, whereas in only 3% (4/121) discrepancies were found in cases forwarded by individual panel pathologists. The percentages erroneously diagnosed Hodgkin's disease by non-panel pathologists and individual panel pathologists were 8 and 0% respectively and faulty diagnosed Non-Hodgkin lymphomas 5 and 0%, whereas the number of consultation cases, in which the referring pathologist was not certain of his diagnosis, appeared to be 24 and 3% for non-panel and panel pathologists respectively. In addition, in 14% of panel confirmed NHL contributed by non-panel pathologists, therapy-relevant discrepancies in the degree of malignancy grading according to the Working Formulation were present, whereas no discrepancies in malignancy grading were noted between individual panel members and panel diagnoses. Apart from extensive hematopathological experience, a reason for the higher diagnostic accuracy of the panel pathologists could well be the frequency in which the diagnoses were supplemented by immunophenotyping: in 22% of the cases from non-panel pathologists and 63% of the cases from panel pathologists immunophenotyping on frozen sections was carried out.(ABSTRACT TRUNCATED AT 250 WORDS)