Brain biopsy in the diagnosis of leptomeningeal involvement in stage I chronic lymphocytic leukemia.

Leptomeningeal involvement of CLL is usually underdiagnosed as neurological symptoms are unspecific. It is important to carefully evaluate neurological status in these patients and consider this entity between the differential diagnosis of a neurological deterioration as adequate treatment improves the prognosis. Imaging techniques, analyses of cerebrospinal fluid, and brain biopsy are useful to establish a definitive diagnosis.