Clinical Pearls & Morning Reports
Intravascular lymphoma is a rare, extranodal subtype of diffuse large B-cell lymphoma. Read the latest Clinical Problem-Solving here.
Q: Is intravascular lymphoma readily identified?
A: The rarity of the disease, its frequently rapidly progressive course, and the nonspecific nature of the presenting symptoms often result in diagnostic delays, and in some cases the disease is identified only at autopsy. The incidence in the United States is less than 1 case per every 10 million persons but has been increasing, possibly owing to heightened awareness since this cancer was categorized as a distinct entity in 2007. The median age of patients at diagnosis is 67 years, and intravascular lymphoma occurs at similar rates among men and women. There are no known risk factors.
Q: What vessels are primarily affected in intravascular lymphoma?
A: Histopathological testing reveals malignant lymphoid cells within the lumina of small vessels, capillaries, and sinusoids of affected organs. It is hypothesized that abnormal expression of adhesion and homing receptors accounts for the localization within these small vessels.
A: Intravascular lymphoma characteristically manifests as fever, pronounced fatigue, decreased appetite, and a decline in functional status. Lymphadenopathy is rarely identified. Many organ systems can be involved. Central nervous system infiltration occurs in 25 to 76% of patients and may result in confusion, gait ataxia, seizure disorders, or memory loss. Pulmonary infiltration results in dyspnea, cough, and hypoxemia. Up to one quarter of affected patients have visible skin lesions, which show substantial heterogeneity, including plaques and nodules, with variation in color, character, location, and number. Geographic variation in phenotype has been noted in series that have been reported from Asian countries and Western countries, which in aggregate have included approximately 200 patients. Hemophagocytosis and a more rapid course are commonly reported in Asian centers, whereas cerebral and pulmonary involvement are more common in Western centers. Anemia and thrombocytopenia are each present in more than half the patients with intravascular lymphoma, and leukopenia develops in one quarter of patients. Elevated serum lactate dehydrogenase levels are present in virtually all patients.
A: Diagnosis requires a tissue biopsy of an involved organ and may involve repeat biopsies. The use of hematoxylin and eosin staining alone may be insufficient for diagnosis. The neoplastic cells are typically B cells with high CD20 expression, occasional CD5 expression, and rare CD10 expression. Therefore, CD20 immunohistochemical staining is typically required for diagnosis. Random (also known as “blind”) skin biopsy, with samples of normal-appearing skin obtained from the thighs, arms, or abdomen has emerged as a valuable, relatively noninvasive diagnostic tool. A retrospective study involving 106 patients showed a progression-free survival rate of 56% and an overall survival rate of 66% at 2 years among patients who had been treated with rituximab-containing chemotherapy regimens (e.g., R-CHOP). There have been no randomized, controlled trials of therapy for this condition. Left undiagnosed, it is fatal.