Fig. 1
A 59-year-old man with pathologically confirmed primary MZBCL of the right cavernous sinus. a Axial contrast-enhanced (CE) brain CT shows a bulging mass lesion (arrowhead) in the right cavernous sinus and measures 2.0 × 3.3 cm in size. b Axial bone window CT image revealed no surrounding skull bone destruction or hyperostosis around the tumor (arrowhead). c Axial CE T1WI shows homogeneous contrast enhancement of the tumor (arrowhead) after gadolinium administration. d The extra-axial origin of the tumor (arrowhead) is identified based on indentation of the right temporal dura (open arrow) on axial T2WI. In addition, encasement of ipsilateral cavernous internal carotid artery is observed without causing narrowing of the vascular lumen (white arrow). e Diffusion-weighted image (DWI) shows isointensity in the tumor (arrowhead). f The measured apparent diffusion coefficient (ADC) value (circular region of interest) is 0.64 × 10–3 mm2/s (b value = 1000 s/mm2), indicating diffusion restriction as compared with brain white matter. g The resected tumor is composed of a diffuse infiltration of small to median-sized lymphocytes mixed with plasma cells (h, e, × 200). h, i Positive staining for pan B cell markers including CD20 (h) and CD79a (i) on immunohistochemical examination (original magnification × 400) are observed. j A stable residual mass with contrast enhancement (curved arrow) is observed on axial CE T1WI 2 years after surgical resection