A case of Mb. Castleman of the localized plasma cell type is reported. This disease expresses several symptoms from different organ systems and therefore an extensive investigation program is often performed. Diagnosis is possible through consideration of all clinical components at the same time: Refractory anaemia, high and refractory SR, weight loss, B-symptoms, but at the same time a relatively good health. CT-scan-demonstration of a localized tumour is an important clue. Histopathologically, the tumour shows vascular hyperproliferation and plasmacytosis of varying maturation. Immunophenotyping of the plasma cells and immunoblasts usually reveals a polyclonal population. Needle biopsies from several regions may be necessary to detect the polyclonality, because monoclonality is often widespread locally in the tumour. HHV8 is correlated to the multicentric PC-type of Mb. Castleman. However, no HHV8 was found in this case.