Intravascular lymphoma (IVL) is a rare form of malignant lymphoma characterized by the selective growth of lymphoma cells within the lumina of vessels, without the involvement of adjacent parenchymal tissue. IVL is predominantly of B-cell lineage, but cases of T-cell or natural killer cell lineage have been described occasionally, predominantly involving the skin. IVL usually affects elderly patients with a poor performance status, elevated serum lactic dehydrogenase levels, anemia, and B symptoms. The clinical presentation varies in different geographical areas, particularly between patients diagnosed in Europe and Asia. In European countries, the Western variant of IVL mainly involves the central nervous system and skin; in particular, there is a "cutaneous variant" limited to the skin. In Asian countries, the Asian variant of IVL predominantly accompanies hemophagocytic syndrome. Identification of this disease is difficult because it presents with non-specific clinical symptoms. Although organ biopsies are mandatory for accurate IVL diagnosis, no standard procedure has been established. An additional random skin biopsy may be useful to diagnose IVL at an early stage. Early diagnosis and treatment can improve the outcome of IVL patients following treatment with rituximab-containing chemotherapy.