A 52-year-old male presented with hypercalcaemia and acute kidney injury. The serum-free kappa chain was 956 mg/L, and the K:L ratio was 119; paraprotein was not detected. A bone marrow aspirate showed excess small lymphocytoid cells (Fig.
1A). They were positive for CD45 and CD56 and negative for CD34, CD19, CD2, CD5, CD7, CD4, CD8, CD33, CD117, CD15, CD13, CD57, surface Ig, MPO, and cTdT (Fig.
1B). Small lymphocyte-like myeloma was suspected, but the addition CD38, CD138 and cytoplasmic Ig could not be performed on flow cytometry due to sample limitation. Targeted CD138 cell FISH showed
IGH::CCND1 fusion (Fig.
1C). Trephine IHC showed CD138+, CD56+, cyclin D1+, CD20+, kappa-restricted small plasma cells (Fig.
1D), confirming the diagnosis of myeloma. Lymphoid NGS identified pathogenic
TP53 p.Glu285Lys (VAF 62%, COSM10722) and
TP53 p.Val272Leu (VAF 19%, COSM10859) variant. The patient had a short response to multiple lines of treatment, refractory to elranatamab and had only two years of overall survival. …
