Neurolymphomatosis of the median nerve, optic nerve, L4 spinal nerve root and cauda equina in patients with B-cell malignancies: a case series

Abstract

Background: Neurolymphomatosis is rare. Neoplastic lymphocytes are seen to invade nerves (cranial or peripheral), nerve roots or other related structures in patients with hematological malignancy. It is a separate entity from central nervous system lymphoma. Neurolymphomatosis has most commonly been described in association with B-cell non-Hodgkin lymphoma. Neurolymphomatosis in the context of Burkitt lymphoma and the post-renal transplant setting has not been described before.

Case reports: We report for the first time in the Arabian Gulf countries and nearby Arab states four cases of neurolymphomatosis (one Asian, and the other 3 are from Arabic nationals) occurring between 2012 and 2017 involving the median nerve, optic nerve, nerve root and cauda equina in patients with Burkitt lymphoma, Philadelphia chromosome-positive B-cell acute lymphoblastic leukemia and diffuse large B-cell lymphoma.

Conclusions: Neurolymphomatosis is rare and can be difficult to diagnose by biopsy but reliably confirmed by a combined imaging approach. Prior treatment with high-dose dexamethasone might suppress 18F-fluorodeoxyglucose (FDG) activity and decrease the sensitivity of positron emission tomography/computed tomography (PET/CT). The prognosis is generally poor but using high-dose methotrexate as well as high-dose chemotherapy and autologous stem cell transplantation may be an effective way to treat neurolymphomatosis.

Keywords: B cell-acute lymphoblastic leukemia (b-ALL); Burkitt lymphoma; Cauda equina syndrome; Diffuse large B-cell lymphoma; L4 spinal nerve root; Median nerve palsy; Neurolymphomatosis; Optic nerve lesion; Post-transplant lymphoproliferative disorder (PTLD); Renal transplant.

Fig. 1

Case 1, radiological findings. a FDG PET-CT. Axial (i) and coronal (ii) planes show abnormally avid activity in the anatomical location of the right upper arm median nerve (arrows). b MRI axial T1-weighted post-contrast fat-saturated image (i). Coronal T1-weighted post-contrast fat-saturated image (ii). The right upper arm median nerve (arrows) is enlarged and displays abnormal signal intensity (low and high T1- and T2-weighted images, respectively) and abnormal post-contrast heterogeneous enhancement (b, i–ii)

Fig. 2

a (i) and (ii) Right median nerve biopsy. Neural tissue shows involvement by lymphoma cells compatible with Burkitt lymphoma. Positivity for CD20 b(i) and Ki67 (ii) is shown. Ki67 expression was 100%.

Fig. 3

Case 2, radiological findings. a MRI brain at presentation. The right optic nerve is thicker than the left one (red arrow). Abnormal enhancement of the optic nerve sheath (tram-track sign) (yellow arrows) extends to the intraorbital and intracanalicular segments of the nerve. There is abnormal enhancement and stranding of the perioptic fat. Axial (i) and coronal (ii) T1-weighted post-contrast fat-saturated images are shown. b MRI brain at clinical progression. Newly developed multiple lesions in the periventricular white matter are noted. Two representative axial T1-weighted post-contrast fat-saturated images are shown

Fig. 4

Case 3: radiological findings. a Post-contrast MRI studies show thickening and intense enhancement of the cauda equina nerve roots predominantly along the nerve sheath seen extending from the conus medullaris region down into the thecal sac to the lumbosacral plexus likely representing perineural tumor spread. Heterogeneous marrow signal pattern of the imaged vertebrae predominantly involving the lower cervical and upper thoracic vertebral bodies, showing bright signal intensity in T2- and STIR weighted images and heterogeneous mosaic pattern enhancement in the post-contrast series with no evidence of structural collapse or extra-osseous soft tissue component. b Post-contrast MRI study 33 months post-autologous stem cell transplant shows almost complete resolution of previously described residual thickening and enhancement of cauda equina nerve roots

Fig. 5

a i, ii Coronal and axial post-contrast fat-saturated images show thickening and enhancement of the right L4 nerve root compared to the left one, which is highly suggestive of lymphomatous infiltration (arrow in a, b)

Fig. 6

a Intense uptake projected to the right L4 spinal nerve root might represent DLBCL relapse (the red arrow is pointing to L4 spinal nerve lesion). b Post-treatment: compared to the previous PET/CT complete remission of DLBCL is evident. Left-sided benign tumor of the parotid gland is noted with no interval change