#00066755

A 60-year-old woman presented, diagnosed with Multiple myeloma (MM), received daratumumab, bortezomib, lenalidomide and dexamethasone with zoledronic acid. Partial results showed no t(11;14) and no del(17p)/TP53 loss. 20 months she developed multiple lytic lesions of the skull and cervical spine, and MRI suggested supratentorial leptomeningeal enhancement.

Cerebrospinal fluid CSF cytospin showing myeloma cells with cytoplasmic projections (May-Grünwald-Giemsa stain) cohesive clusters of large, round, atypical plasma cells. The nuclei are round with coarse, dark chromatin and a high nuclear-to-cytoplasmic ratio, and the cytoplasm is scant and basophilic. Many cells have fine, short, hair-like cytoplasmic projections around their circumference, and long thin filaments radiate from the cluster into the background. Microscopic examination of the CSF revealed an infiltration by MM cells (panel A to F).