Approach at lymph node pathology and ancillary techniques Hans Konrad Müller-Hermelink Institute of Pathology, University of Würzburg Würzburg, Germany 1000 km 400 km Würzburg Germany: 80.000.000 population Würzburg: 200.000 population ….contemporary lymphoma diagnosis integrates histology, immunophenotype, (molecular) genetic data as well as clinical features … Frequency of lymph node diseases in primary material Lymphadenitis 6141 56% Metastasis 2658 24% Lymphoma 1636 15% B-cell line: 65% T-cell line: 8% Hodgkin: 27% Granulomatous lymphadenitis 357 3% Other infectious types of lymphadenitis 230 2% Autoimmune disease 28 <1% Reactive Hyperplasias and Reaction Patterns in different compartments Sinus reactions B-cell compartment • Sinus histiocytosis • Follicular hyperplasia • Foreign body reaction • Sinusoidal B-cell reaction • Mastozytosis • Marginal zone reaction/ nodules • Sinus lymphocytosis • Extrafollicular B-cell activation Macrophage reactions • Plasmacytosis • Foreign body reactions • Progressive transformation of • Epitheloid cell reactions germinal centres • Purulent granulomas T-cell compartment • Nodular paracortical hyperplasia • Diffuse paracortical hyperplasia – CD 4 dominant DTH activation – CD 8 dominant cytotoxic activation