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Home : Diagnostic References : Imaging of Cerebral Tumors : Lymphomas and hematopoetic neoplasms
     
 Table of Contents
Primary CNS lymphoma
  Overview
  Case report 1
Case report 2
  Case report 3
Leukemia
References: lymphomas and hematopoetic neoplasms
 
Primary CNS Lymphoma: Overview
published: June, 1999
by: G. Wilms
 
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Incidence

They account for 1-2% of all intracranial neoplasms.

Macroscopic appearance and general characteristics

Primary CNS lymphomas are lymphomas with the same histological characteristics of systemic lymphomas, but occurring without concomitant extracranial disease. Primary lymphomas of the brain are usually intraparenchymal, whereas lymphoma metastatic to the CNS is typically meningeal. The lesions are deep-seated, often subependymal. Bilateral symmetrical involvement is possible. The growth pattern is diffuse rather than nodular. Multiple lesions and tumors with widespread necrosis are more likely to be associated with AIDS. Lymphomas are classified according to the classification of lymphomas elsewhere in the body. Most lymphomas are non-Hodgkin lymphomas.

Microscopic appearance

CNS lymphomas histologically resemble systemic lymphomas. They are almost exclusively non-Hodgkin lymphomas, mostly large monoclonal B-cell lesions.

Imaging features (see case reports)

On CT scan the lesions are typically described as isodense to hyperdense before contrast and variably enhancing. On MRI, primary CNS lymphoma presents as solitary or multiple lesions that abut an ependymal surface (image 8). Enhancement is intense and homogeneous. On unenhanced T1 and T2 weighted images, the enhancing area has different signal characteristics than the surrounding tissue. The central zone is believed to correspond to densely packed tumor cells, while the surrounding corresponds to increased water content, and infiltrating tumor cells. Ring enhancement is more commonly seen in patients with AIDS. Imaging findings can be very similar to high-grade astrocytoma or metastasis and secondary CNS lymphoma.

Differential diagnosis

The main differential diagnosis of multiple lesions includes metastasis or non-neoplastic inflammatory or infectious lesions such as sarcoidosis, tuberculosis or toxoplasmosis, cysticercosis or other concomitant infections in AIDS. For solitary lesions, the main differential diagnosis is glioblastoma.

Case reports

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