“Rod-Like” Cytoplasmic Crystals of Peripheral Lymphocytes in Chronic Lymphocytic Leukemia

could be observed in the cytoplasm or covering the nuclei in lymphocytes (Figures 1A-1D). Abdominal computed tomography showed multiple enlarged lymph nodes in the abdomen and groin. Flow cytometry analysis revealed the expression of CD19, CD20, CD5, CD22, CD23, CD24, CD38, lambda, FCM7 (dim, 38.6%), and CD200 (high). Previous studies have suggested that the formation of crystals may be related to dysfunctional immunoglobulin (Ig) synthesis [1,2,3,4]. In our case, the levels of IgG, IgA, and IgM were all reduced, with the most significant reduction seen for IgG at 4.96 g/L. While some observations of similar rod-like structures have been reported in cases of B-cell lymphoproliferative diseases, intracellular rod-like crystals in mature lymphocytes in CLL are extremely rare in peripheral blood [5,6,7]. Here, the crystals in the lymphocytes were present after anti-leukemia therapy. Whether the formation of these crystals may be related to chemotherapy drugs needs to be confirmed.