NK-cell intravascular lymphomatosis--a mini-review.

The majority of cases of intravascular lymphomatosis (IVL) is derived from B cells. However, IVL may also arise from T cells, or more rarely NK cells. The clinicopathological findings in six cases of NK-cell IVL (NK-IVL), including one new case, were summarised and compared with B-cell IVL (B-IVL) and T-cell IVL (T-IVL). Earlier onset of disease and female predominance were found in NK-IVL. NK-IVL was typically Epstein-Barr virus (EBV)-positive, whereas EBV was rarely detected in B-IVL. Cutaneous manifestations were common in NK-IVL with constant EBV infection. B-IVL showed a more favourable prognosis than T- or NK-IVL. Irrespective of immunophenotype, however, IVL showed a less favourable prognosis than ordinary lymphomas within the same immunophenotype. In summary, IVL of the B-, T- and NK-cell phenotypes is clinicopathologically distinct and shows similarities to their more common counterparts, i.e. diffuse large B-cell lymphoma, peripheral T-cell lymphoma, unspecified and extranodal NK/T-cell lymphoma, nasal type.