• HAEMATOPATHOLOGY
• MYELOMA
• BONE MARROW
• CYTOGENETICS

A female patient presented with bone pain. Bone scan demonstrated a focal lesion in the left iliac crest, which was confirmed subsequently as a lytic lesion on CT scanning. Core biopsy showed plasmacytoid cells that were strongly positive for CD138 with extensive strong κ light chain immunostaining. Haemoglobin was 124 g/L, white cell count 5.4×10⁹/L, neutrophils 3.0×10⁹/L, platelets 300×10⁹/L and erythrocyte sedimentation rate 7 mm/h. Serum creatinine was 90 μmol/L; adjusted serum calcium was 2.50 mmol/L with normal serum phosphate and bicarbonate levels and anion gap. Serum protein electrophoresis demonstrated monoclonal IgG κ of 4 g/L and free κ light chain of 5 g/L. Urinary Bence–Jones protein measured 2.45 g/L comprising free κ light chains. Serum free κ light chains were >4275.0 mg/L (3.3–19.4) and λ light chains 9.4 mg/L (5.7–26.3) with β₂-microglobulin 5.4 mg/L (0.80–3.00). Skeletal survey demonstrated multiple lucencies in both femora, humeri, ribs, thoracic spine, calvarium and left iliac bone.

Six years previously, she …