Case of the Month
Section Editor: Nicholas Stence, MD
Children's Hospital Colorado, Aurora, CO
May 2020
Next Case of the Month Coming June 9...
Intravascular Large B-Cell Lymphoma
- Background:
- Intravascular lymphoma (IVL) is a rare subtype of extranodal diffuse large B-cell lymphoma, in which the malignant lymphocyte clone is restricted to the lumen of small and medium-sized blood vessels.
- Although a systemic disease, the skin and CNS are the most frequently affected sites.
- Early diagnosis is critical to altering the disease course; however, the diagnosis is challenging and frequently made at autopsy.
- Clinical Presentation:
- Premortem diagnosis of IVL is difficult because of its variable clinical manifestations.
- B symptoms (fever, night sweats, and weight loss) are sometimes present.
- Over 60% of patients develop neurologic manifestations at some point in their disease course, including encephalopathy, seizure, myelopathy, radiculopathy, or neuropathy.
- Key Diagnostic Features:
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IVL represents a diagnostic challenge because of its heterogeneous clinical manifestations and lack of specific laboratory and imaging findings.
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A proper diagnosis of IVL is determined by tissue biopsy.
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Inflammatory markers and lactate dehydrogenase may be elevated but are nonspecific in isolation.
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Given the tendency of B-cells in IVL to remain intravascular, PET is usually negative.
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Cerebral MR imaging findings in patients with IVL are also diverse:
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scattered, infarctlike lesions (multifocal DWI lesions in association with T2 signal abnormalities, confirming the diagnosis of small vessel ischemia or infarction)
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nonspecific white matter lesions (poorly defined, especially in the periventricular area)
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masslike lesions (intraparenchymal masslike lesions presented with vasogenic edema and mass effect)
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hyperintense lesions in the pons on T2WI (in the central pons, without enhancement or diffusion restriction)
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meningeal/focal parenchymal enhancement (appearing in proximity to the T2 or DWI changes and persisting or enlarging over weeks to months)
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Gadolinium enhancement is dependent upon timing of MRI and in less than one-third of cases was seen on the initial MRI scan and the follow-up scan revealed enhancement in another 10%.
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Hemorrhagic foci are uncommon.
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- Differential Diagnoses
- CNS vasculitis and IVL show a marked overlap of clinical presentation, laboratory findings, and imaging appearance.
- Both conditions cause small vessel infarctions scattered throughout the supratentorial and infratentorial compartments or the spinal cord. (MRI alone cannot solve this diagnostic dilemma.)
- CNS vasculitis and IVL show a marked overlap of clinical presentation, laboratory findings, and imaging appearance.
- Treatment:
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Anthracycline-based multiagent chemotherapy along with rituximab (R-CHOP) is the most commonly used regimen, with reported complete response rates and 2-year overall survival rates of 80% and 60%, respectively.
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Nevertheless, IVL is an aggressive lymphoma with a dismal prognosis and CNS involvement portends a poor prognosis.
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