Occult large epiphyseal solitary plasmocitoma at multidetector row computer tomography detected by magnetic resonance imaging.

Myeloma or Kahler-Bozzolo disease represents around 1% of all malignant tumors and 10% of the haematological variety; it is a B-lymphocellular malignant neoplasia which originates from plasma cells that produce monoclonal immunoglobulin, infiltrating in and destroying the adjacent bone tissue.Myeloma may be distinguished at radiological imaging in four distinct types: single osseous lesions (solitary plasmacytoma), diffused skeletal effects (myelomatosis), diffused osteopenia and sclerosing myeloma. It is known that initial osteolysis may not be shown through radiographic examination or CT; the lysis only becomes evident when there is a bone loss of over 50%, usually in the presence of a =/> 0,5 cm focal lesion.We present here the clinical-radiological aspects of a solitary bone plasmacitoma (SBP) of the knee of a 35 year old male which was not evidenced at radiological examination or CT but was evident as a 3 cm focal alteration at MR. The lesion was confirmed by PET and the histological diagnosis was performed by a CT guided bioptic sample.