Intravascular lymphoma (IVL) is a rare form of non-Hodgkin lymphoma characterized by massive proliferation of large, neoplastic cells in small-and medium-sized blood vessels. Most cases of IVL are of B-cell immunophenotype; fewer than 15 cases of T-cell IVL have been reported. A 23-year-old male presented with acute abdominal pain, fever, and tender lower abdomen. Pathology at laparotomy revealed infiltration of colonic vessels with large lymphoid cells compatible with IVL. We reviewed all cases of IVL diagnosed at the Queen Elizabeth II Health Sciences Centre in Halifax, Nova Scotia, from August 1992 to August 2002. A literature review was also performed. Five additional cases of IVL were identified at this institution during a 10-year period. Three patients presented with neurological symptoms, and two with abdominal pain. In 4 of 5 cases, patients died of lymphoma within 3 months of presentation; one patient experienced a 10-month remission. While visceral involvement with IVL is common at autopsy, IVL presenting as an acute abdomen in an immunocompetent patient has not previously been described. Among the 15 cases of T-cell IVL reported in the literature, only two occurred in people under age 30. Given the rarity of T-cell IVL, it is remarkable that three cases of T-cell IVL have been diagnosed at our institution during a 10-year period. Am.