T-cell prolymphocytic leukemia presenting with leukemic serous effusion in a prostate cancer patient.

T-cell prolymphocytic leukemia (T-PLL) is highly aggressive mature postthymic lymphoproliferative disorder, which is characterized by several clinical features. Leukemic prolymphocytes are found in the peripheral blood, bone marrow, lymph nodes, spleen, liver, and sometimes skin. T-PLL and solid tumor coincidence was reported by only four previous cases. Solid tumor components included breast cancer, classic Kaposi sarcoma, gastric cancer, and lung cancer in those cases. We report the first case of T-PLL, an extremely rare disease, presented with serous effusion in an elderly prostate cancer patient in literature.