Comparison of lymphoid neoplasm classification. A blinded study between a community and an academic setting.

The revised European-American classification of lymphoid neoplasms has been reported as reproducible among expert pathologists and feasible in a community setting. We evaluated the reproducibility of lymphoid neoplasm diagnoses between a community and an academic center. We subtyped 188 lymphoid neoplasms using revised European-American classification criteria. Clinical findings, histologic or cytologic preparations, paraffin-section immunostains, and flow cytometry data were reviewed as appropriate. Diagnoses were compared only after completion of the study. Lymphoma subtype was concordant for 167 (88.8%) of 188 cases. Discordant cases included 15 B-cell, 2 T-cell, and 4 Hodgkin lymphomas. For B-cell neoplasms, discordance was most often due to classifying diffuse large cell lymphoma as another aggressive subtype of lymphoma (n = 6), marginal zone lymphoma as another subtype (n = 4), or follicle center lymphoma grade II as grade III (n = 3). For Hodgkin disease, discordance was most often due to classifying nodular sclerosis as mixed cellularity type (n = 3). Comparison of community and academic center diagnoses demonstrated high concordance for most revised European-American classification subtypes. Some sources of discordance have been addressed in the new World Health Organization classification of neoplastic diseases of the hematopoietic and lymphoid tissues.