Background: Unusual morphological variants of plasma cell myeloma are a diagnostic challenge.Case presentation: A 60 year old woman with low-back pain was diagnosed with a plasma cell myeloma in the bone marrow. Concurrently a tumour was found in the liver. The histological specimen of the liver resembled a clear cell carcinoma, but the immunophenotype revealed plasma cell myeloma.Conclusion: In tumours with an extraordinary morphology and not conclusive immunohistochemical results the use of plasma cell antibodies may lead to the correct diagnosis.