Central nervous system involvement in multiple myeloma as a first manifestation of relapse and potential diagnostic pitfall.
Jessy Ranaivomanana, Léa Ryffel, Muriel Newinger et al.
✦ AI-curated · Sources linked
Case in brief
In a review of 459 patients with multiple myeloma, four had cerebrospinal fluid involvement by malignant plasma cells. Three were in complete remission when CNS disease was detected. Neurological presentations did not always correspond to cerebral lesions on imaging; one patient had spinal cord compression. Morphology and flow cytometry supported the diagnosis, although flow-cytometric interference in two cases was consistent with daratumumab entering the CSF. CSF IL-6 was elevated in some cases, while IL-10 was low or undetectable. Overall prognosis was poor: three patients died, and one was alive at 2 years.
What made this case unusual
CNS involvement was detected during complete remission and could be present despite negative cerebral imaging. Daratumumab-associated interference also complicated flow-cytometric assessment.
Diagnostic / clinical pearl
Consider CNS myeloma in patients with unexplained neurological symptoms, even when imaging is negative; interpret CSF flow cytometry with awareness that anti-CD38 therapy may interfere with analysis.