Background: Involvement of the central nervous system (CNS) is a rare complication of chronic lymphocytic leukemia (CLL) and seems to be more frequent in patients with Richter's syndrome or prolymphocytic transformation. Cases with leptomeningeal involvement reported in the literature mostly do not discuss the definition of CLL-associated meningeosis and the exclusion of neuroborreliosis.
Patient and methods: We present the case of a 75-year-old male patient who was admitted to a rural hospital with ataxia, disorientation, and signs of progressive CLL disease. He was diagnosed of suspicious meningeosis leukemica, and treatment was started with dexamethasone for leukemic CNS involvement.
Results: When referred to our center, careful immunophenotyping of the CNS lymphocytes as well as assessment for infectious causes of lymphocytic meningitis led to the diagnosis of Lyme disease/neuroborreliosis. An antibiotic regimen with ceftriaxone for 3 weeks resulted in complete remission of all symptoms. There was no need for CLL treatment.
Conclusion: In conclusion, this case report should alert clinicians that lymphocytic meningeal involvement in CLL patients accounts for the rare leukemic meningeosis only if cerebrospinal fluid cells show a predominating immunophenotype of typical BCLL cells, i.e. by flow cytometry, and if any infectious cause including Lyme disease has been ruled out.