Intravascular NK/T-cell lymphoma: a series of four cases.

Intravascular natural killer/T-cell lymphoma (IVNKTL) is a rare disorder and is reported gradually increased recently. We presented four cases including two extremely rare cases of primary lung IVNKTL with detailed clinicopathological features, therapy and prognosis, and reviewed the literature for 25 similar cases. H&E, Immunohistochemical staining and in situ hybridization (ISH) were used in the study. The medium-sized lymphoid cells were characterized by the selective growth within the kumina of vessels, particularly capillaries. The endothelial cells in the vessels exhibited positive CD34 staining. The lymphoid cells were positive for NK/T-cell markers, and cytotoxic proteins, and negative for B-cell markers. ISH demonstrated that the lymphoid cells expressed EBER. All the patients died of the disease a few months later. To conclude, the overall survival of patients with IVNKTL is very poor and the 1-year survival rate is only 31%. Patients with B symptoms and multiple organs involvement may be associated with the poor clinical prognosis. We deduce that the traditional chemotherapy with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP) is inadequate for the treatment of IVNKTL. Early accurate diagnosis by biopsy for this lymphoma may be crucial for the patients' medical prognosis due to the fatal disease course. IJCEP