Spindle cell morphology in myeloma

An 87-year-old man who had been under urological follow-up with a raised prostate-specific antigen was referred to haematology widespread infiltrative bone disease, sternal and vertebral fractures normocytic anaemia. He two-year history of pain, which worsened in the previous two months. Serum protein electrophoresis revealed an immunoglobulin (Ig) A lambda paraprotein at too low concentration quantify. The patient also immune paresis. serum free kappa light chains were 3·9 mg/l (normal range 3·3–19·4) 3.55 (5·7–26·3). Haemoglobin 89 g/l, creatinine 128 µmol/l corrected calcium 2·39 mmol/l. marrow aspirate haemodilute no apparent excess plasma cells seen, but flow cytometry identified 6·5% cells, positive for CD38 CD138 negative CD45, CD19 CD27. Bone trephine biopsy sections showed suppression haematopoiesis interstitial infiltrate elongated spindle morphology, suggestive neuroendocrine malignancy or perhaps sarcoma, cytomorphological similarities (left, haematoxylin eosin, ×40 objective). However, these (right, immunoperoxidase, ×20), MUM1 IgA heavy chain, confirming that neoplastic bony disease due multiple myeloma. Interestingly, strongly cyclin D1-positive CD79a, lambda-negative, despite level plasma. Given age frailty patient, he is being treated lenalidomide dexamethasone.