[Clinicopathologic features of intravascular large B-cell lymphoma in Japan: review of the special reference to the Asian variant].

The Asian variant of intravascular large B-cell lymphoma (IVL) is characterized by hemophagocytic syndrome, i.e. the clinical features include pancytopenia, hepatosplenomegaly, and rarely mass formation. It usually lacks any neurological abnormality or skin lesions, which are typical features of classical IVL. Sixty-seven cases of IVL reported in Japan since 1990 were classified into two groups, and their clinicopathologic features were compared. Forty-five cases of IVL that met the clinical and laboratory criteria for the Asian variant were classified into Group A (average: 66 yr; male: 62%), and 22 cases that did not meet the criteria were classified into Group C (average: 65 yr; male: 73%). Hemophagocytosis was described only in Group A. The positivity rates for bone marrow invasion, fever, hyperbilirubinemia and elevated levels of LDH and CRP were significantly (p = 0.0037, p < 0.0001, p = 0.0428, p = 0.0108 and p = 0.0008, respectively) higher in Group A than in Group C. On the other hand, the positivity rates for neurological abnormality and skin lesions were significantly (p < 0.0001 and p = 0.0011, respectively) higher in Group C than in Group A. Our reassessment of the reported cases of IVL in Japan identified two major categories of IVL: the classical form and the Asian variant.