Magnetic resonance features of primary central nervous system lymphoma in the immunocompetent patient: A pictorial essay

Abstract

Primary central nervous system lymphoma (PCNSL) is an uncommon but important variant of non-Hodgkin lymphoma and represents up to 6% of all primary central nervous system (CNS) malignancies. Recognition of this entity by radiologist on MRI may avoid unnecessary neurosurgical resection and redirect to biopsy. The pretreatment MRI of patients with biopsy proven PCNSL from the last 5 years at our institution was reviewed. Selected examples were used to construct a pictorial essay to illustrate some of the typical and atypical MR features of PCNSL. MRI of other CNS conditions with imaging similarities to PCNSL was included to demonstrate possible mimics. The typical features of PCNSL lymphoma are intra-axial homogenous single or multiple contrast enhancing lesions, with marked surrounding oedema and restricted diffusion, usually contacting a cerebrospinal fluid (CSF) surface. Necrosis, peripheral enhancement, haemorrhage or calcification are unusual and other diagnoses should be considered if any of these features are present. Potential mimics include high grade glioma, infarcts, metastatic disease, demyelination, abscess and secondary lymphoma. Careful assessment of the MR features and correlation with the clinical findings should enable the radiologists to raise the possibility of PCNSL and minimise the risk of unnecessary resection.

“Dazed and diffused”: making sense of diffusion abnormalities in neurologic pathologies

“…In addition, lesions are solitary in approximately 60-80% of cases [55,56], demonstrate homogeneous enhancement in up to 90% of cases and rarely demonstrate necrosis, haemorrhage or calcification [55,56,59]. Lesions are typically distributed in a periventricular location and may involve the corpus callosum [55,56]. Imaging of primary CNS lymphoma in the immunocompromised patient demonstrates similar findings, although multiplicity of lesions, peripheral enhancement, necrosis and haemorrhage are more often seen [55,59].…”

“…Primary central nervous system (CNS) lymphoma accounts for 1-5% of all primary malignancies of the CNS, with diffuse large B-cell non-Hodgkin lymphomas representing .95% of primary CNS lymphomas [55,56]. The mean age at onset in immunocompetent patients is 50-60 years, whereas in immunocompromised patients, the mean age is in the thirties [56,57].…”

“…The mean age at onset in immunocompetent patients is 50-60 years, whereas in immunocompromised patients, the mean age is in the thirties [56,57].…”

“…Lesions typically demonstrate restricted diffusion on MRI, a finding attributed to the high cellularity of the lymphomas [55,58] (Figure 7). In addition, lesions are solitary in approximately 60-80% of cases [55,56], demonstrate homogeneous enhancement in up to 90% of cases and rarely demonstrate necrosis, haemorrhage or calcification [55,56,59]. Lesions are typically distributed in a periventricular location and may involve the corpus callosum [55,56].…”

An Unusual Location of a Primary Central Nervous System Lymphoma: The Temporal Horn

“…The typical features of PCNSL were intra-axial homogenous single or multiple contrast enhancing lesions, with marked surrounding edema and restricted diffusion, usually contacting a cerebrospinal fluid (CSF) surface. The frontal lobe was most frequently involved [5]. In this case, MR finding of temporal horn tumor was corresponded to intra-axial single lesion of ovoid shape with homogenous enhancement and surrounding edema.…”