Neurolymphomatosis: An unusual cause of multiple nerve thickening

10-year-old boy with complaints of left sided facial pain and body pain for 1 month.

He also had difficulty swallowing, deviation of the angle of the mouth, occasional vertigo, headache, and significant weight loss.

Clinical examination revealed multiple cranial palsy (left V, IX, X, XI and right VII).

Brain CT revealed a hyperdense lesion in the left middle cranial fossa in the parasellar region extending to left parapharyngeal location, causing widening of foramen ovale.

Brain MRI showed multiple cranial nerve thickening with lesions along the course of the bilateral trigeminal nerves, on left side starting from its cisternal segment, extending to left cavernous sinus, further inferiorly, along the mandibular division, forming a large mass in the parapharyngeal space and on right side, involving cisternal and cavernous segments, which is smaller in size. The lesion appears T1 hypointense, T2 isointense shows diffusion restriction and homogeneous enhancement. Imaging of spine showed thickening of spinal nerve roots from L1 to S1 levels. An extradural deposit was noted posterior to L3 vertebral body.

Histology came out as Burkitt’s lymphoma. Patient was started on chemotherapy. Repeat MR study shows significant reduction in size of the lesion and the nerve thickening.

Neurolymphomatosis was first described in 2003 as a rare syndrome of lymphoma and leukaemic infiltration of cranial or peripheral nerves. Until that report, lymphoma infiltration in the roots and nerves had not been clearly differentiated from paraneoplastic or therapy-related nerve disorders. A primary neurolymphomatosis is defined as the first manifestation of the haematologic malignancy, whereas a secondary neurolymphomatosis is defined as a site of relapse or the progression of a previously diagnosed lymphoma or leukaemia (1).

Neurolymphomatosis (NL) is generally a manifestation of an unknown or known B cell non-Hodgkin’s lymphoma (NHL), and rarely T-cell lymphoma. It is a rare clinical entity and the incidence is 0.2% of all NHL patients. (2) NL typically presents with any of the 4 clinical scenarios:

Painful or painless peripheral mononeuropathy or mononeuritis multiplex, painful peripheral polyneuropathy or polyradiculopathy, painless polyneuropathy, and painful or painless cranial neuropathy (2).

The major differential diagnosis of cranial nerve hypertrophy, with or without enhancement, includes neoplastic disease (such as metastatic disease and lymphoma) and neurofibromatosis type 1. The degree of cranial nerve enhancement, smooth versus irregular nerve enlargement, and the presence or absence of associated leptomeningeal disease may help in narrowing the differential (3).

When the nerves are significantly thickened, neoplasms (Primary/metastatic) dominate the aetiologies. Diffusion restriction of lesions on DWI sequences with corresponding lower ADC values, if present, has been shown to be associated with lymphoma more consistently than other tumours and metastatic lesions, but tissue diagnosis is mandatory. Clinically, NL mimics non-neoplastic and paraneoplastic neuropathies (4).

Written patient consent for this case was waived by the Editorial Board. Patient data may have been modified to ensure patient anonymity.