Differentiating between Lymphoma and Metastasis Presenting as Solid Cerebellar Mass Lacking Necrosis.

Area of Science:

• Radiology
• Neurology
• Oncology

Background:

• Differentiating cerebellar masses between primary central nervous system lymphoma (PCNSL) and metastasis is clinically important.
• Solid enhancing cerebellar masses lacking necrosis present a diagnostic challenge.

Purpose of the Study:

• To identify distinct radiologic features on contrast-enhanced MRI that differentiate PCNSL from metastasis in the cerebellum.
• To evaluate the diagnostic performance of specific imaging signs, including the 'serrate sign'.

Main Methods:

• Retrospective analysis of 24 PCNSL and 32 metastasis cases with solid, non-necrotic, enhancing cerebellar masses.
• Evaluation of imaging characteristics on contrast-enhanced MRI, defining the 'serrate sign' as tumor spread along white matter with branch-like enhancement.

Main Results:

• The serrate sign was exclusively found in PCNSL (75.0%) versus metastasis (0%, p < 0.001).
• Homogeneous enhancement was more frequent in PCNSL (91.7%) compared to metastasis (21.9%, p < 0.001).
• Bulging contour and surface involvement were more indicative of metastasis.

Conclusions:

• The serrate sign and homogeneous enhancement are reliable MRI indicators for differentiating cerebellar PCNSL from metastasis.
• The serrate sign shows high sensitivity (75.0%) and specificity (100%) for PCNSL detection.