Diffuse large B-cell lymphoma of the cauda equina

Abstract

Primary central nervous system (CNS) lymphoma is a rare form of non-Hodgkin's lymphoma. The clinical presentation is variable, depending on its localisation within the nervous system. Only 1% of primary CNS lymphoma emerges in the spinal cord, and the prevalence of primary lymphoma of the cauda equina is unknown, but probably even rarer. Diagnosing primary lymphoma of the cauda equina is difficult, since it can mimic other more common disorders such as a herniated disc, especially in its early stages. Here we present two cases of primary cauda equina lymphoma in which diagnostic work up took a long time, as the final diagnosis was only reached after a nerve root biopsy.

Figure 1

Upper part showing a sagittal (left) and transversal (right) T2-weighted MRI image of the lumbosacral region of the patient in case 1, without extreme thickening of the nerves. The lower part shows the T1-weighted image after intravenous gadolinium with clear enhancement of the cauda equina.

Figure 2

Upper part displays H&E low-power magnification (left) and H&E high-power magnification (right) showing nerve infiltration with medium to large tumour cells with little cytoplasm, large nuclei and prominent nucleoli. Lower part showing immunohistochemistry positive for CD20, suggesting B-cell origin of the tumour cells.

Figure 3

MRI of the lumbosacral region in case 2. There is also extreme thickening of the nerves with clear enhancement after intravenous gadolinium.

Figure 4

Positron emission tomography (lower part) and corresponding CT image (upper part) of the patient in case 2. Note the increased fluorodeoxyglucose load at the lumbosacral nerve roots.

Figure 5

Case 2, H&E magnification also showing nerve infiltration with tumour cells with little cytoplasm. Lower part showing immunohistochemistry positive for CD-20, suggesting B-cell origin of the tumour cells.