In plasma cell myelomas, immunophenotyping by flow cytometry can not only provide diagnostic and prognostic information but it can also detect minimal residual disease following therapy. Neoplastic plasma cells usually lack surface immunoglobulins although the case presented here has dim kappa (right panel). There was strong cytoplasmic expression of kappa light chains (see next image). In contrast, the normal and reactive plasma cells have polyclonal pattern of cytoplasmic immunoglobulins. Image courtesy of: Genevieve Crane, MD, PhD, Johns Hopkins Hospital, Baltimore, Maryland, USA.