Factors influencing timely diagnosis in neurolymphomatosis.

Background: Neurolymphomatosis refers to infiltration of the peripheral nervous system (PNS) by non-Hodgkin lymphoma (NHL). Diagnostic intervals in neurolymphomatosis and factors delaying diagnosis have not been evaluated. We therefore aimed to analyze diagnostic intervals in a large cohort.

Methods: The quality control database at Yale Cancer Center, Section of Neuro-Oncology, was searched for neurolymphomatosis cases diagnosed between 2001 and 2021. Univariate analyses were performed to identify parameters influencing diagnostic intervals.

Results: We identified 22 neurolymphomatosis cases including 7 with primary and 15 with secondary disease, which occurred a median (range: 4-144) of 16 months after initial NHL diagnosis. Patients typically presented with painful polyneuropathy (73%), that was asymmetrical and rapidly progressive. Diagnosis was based on PNS biopsy (50%) or integration of neuroimaging findings (50%) with NHL history and diagnostic cerebrospinal fluid examinations. Median interval from symptom onset to diagnosis was 3 months (range: 1-12). Secondary neurolymphomatosis compared to primary disease (median 2 vs. 6 months, p = 0.02), and cases with rapidly-progressive asymmetrical neuropathy as opposed to other presentations (median 2 vs. 6 months; p < 0.001) were diagnosed earlier. Upfront conventional CT compared to other modalities (median 2 vs. 5 months p = 0.04) and nerve root localization as opposed to other disease sites (median 1.5 vs. 4 months; p = 0.04) delayed diagnosis.

Conclusions: NL type and localization, neuropathy course and distribution, and imaging modality selected for initial evaluation influence diagnostic intervals in neurolymphomatosis. Knowledge of this rare entity is critical for early suspicion, and diagnosis.