Circumdural extension of perineural spread leading to bilateral disease in neurolymphomatosis

Patients with neurolymphomatosis (NL) often present with one primarily symptomatic limb but can be found to have bilateral upper or bilateral lower limb disease during workup. We sought to explain the finding of bilateral disease and understand if there was a connection to the initial, symptomatic side of disease.

We reviewed imaging studies of patients with bilateral upper or bilateral lower limb disease from a previously published cohort from our institution, as well as more recent patients seen at our institution. We reviewed demographics (sex and age), clinical data (primary or secondary disease and biopsy-proven diagnosis), and imaging findings (primary involved nerve, contralateral nerve(s) affected, and location of circumdural extension).

We identified 8 cases with evidence of bilateral disease out of 22 cases of tumefactive NL. All eight cases were found to have circumdural extension of disease to the corresponding contralateral nerve.

We describe the pathomechanism of spread in our cases of bilateral upper or bilateral lower limb disease, where NL spreads along a dominant nerve toward the spinal canal and moves circumdurally to affect the corresponding contralateral nerve. We believe this information is useful to further understand the spread of NL, as well as offering important diagnostic and prognostic information for patients.