Crystalline inclusions in B monoclonal lymphocytes.

A 88-year old woman presented with malnutrition and depressive psychosis. No lymphadenopathy nor hepatomegaly or splenomegaly was noted on clinical examination. A blood count showed haemoglobin 12.6 g/dL, haematocrit 0.38, WBC 6.6×10/L with the lymphocyte count 1.6×10/L and platelet count 184×10/L. Twenty percent of the lymphocytes showed large cytoplasmic inclusions which appeared rectangular or square, unstained structures in May Grünwald Giemsa staining (photographs). An immunophenotyping performed on blood lymphocytes revealed 30% of clonal lambda-lymphocytes expressing CD19, CD20, CD22, CD23 but not CD5, and allowed the diagnosis of a chronic lymphoproliferative disorder. No cryglobulinaemia was detected. Crystalline inclusions in lymphocytes of lymphoproliferative disorders are not uncommon; they represent crystallized immunoglobulin.