Title : Lymphomatosis cerebri mimicking CNS demyelination: Case series and literature review
Abstract:
Background: Lymphomatosis cerebri is a variant of primary central nervous system lymphoma that is characterized by diffuse infiltrates without a mass formation that is often seen. It poses a diagnostic challenge because the radiological findings are not typical for lymphoma.
Methods: We discuss three cases of Lymphomatosis cerebri and perform a literature review.
Results: The ages of the patients were 41, 42, and 48 years, respectively, of whom 2 were women(41, 42). All three of them had ataxia and diplopia at onset, and eventually progressed to have bulbar palsy with quadriplegia. One patient presented with cognitive impairment and seizures. The mean duration of illness was 2.5 months. One of them had a 12-year history of rheumatoid arthritis and was on weekly methotrexate. MRI Brain of all patients showed bilateral subcortical hyperintensities along white matter tracts extending into the brainstem showing patchy areas of diffusion restriction, and increased uptake on PET-CT. Demyelination was suspected and all of them received immunotherapy, either first or second line or both. One of them was treated with cyclophosphamide with transient improvement. Two of them succumbed to complications of prolonged ventilation and one remains in a minimally conscious state on ventilatory support. Biopsy may be challenging in such cases considering brainstem lesions and deep white matter lesions at the onset of illness. With clinical progression, surgically accessible brain lesions may appear, by which time significant clinical deterioration has already occurred. In our patients, this was the main limitation, and we were unable to perform a biopsy. However, an early diagnosis based on clinical features and specific radiological signs is likely possible, with reasonable exclusion of other differentials, consistent with previous reports.
Conclusion: It is often diagnosed as an inflammatory or demyelinating disorder contributing to the delay in initiating anticancer therapy. Rapid clinical progression, a lack of response to steroids, infiltrating lesions with diffusion restriction, and increased activity on PET are highly predictive of lymphoma.
Audience Take Away Notes:
- To recognise red flags for demyelination
- Interpretation of radiological signs and common pitfalls in diagnosing Lymphomatosis cerebri
- A simplified algorithm to guide clinical judgment in suspected cases of CNS demyelination to rule out close differentials, i.e, vasculitis, infections and neoplasms
