[Role of computerized tomography in the diagnosis of bone disease in multiple myeloma]

To assess the role of CT in the diagnosis and management of multiple myeloma (MM) and to investigate if CT findings can influence the clinical approach, prognosis and treatment.

We reviewed the findings relative to 273 MM patients submitted to CT June, 1994, to December, 1996. The patients were 143 men and 130 women (mean age: 65 years): 143 were stage I, 38 stage II and 92 stage III according to Durie and Salmon's clinical classification. All patients were submitted to blood tests, spinal radiography and CT, the latter with serial 5-mm scans on several vertebral bodies. The CT unit was a Philips Tomoscan SR 7000.

CT showed lysis foci in some vertebral bodies (4 cases) where conventional radiography had shown only aspecific osteopenia. CT also depicted vertebral arch and process involvement in 3 cases with the vertebral pedicle sign. Moreover, CT proved superior to radiography in showing the spread of myelomatous masses into the soft tissues in a case with solitary permeative lesion in the left pubic bone, which facilitated subsequent biopsy. As for extraosseous localizations, CT demonstrated thoracic soft tissue (1 woman) and pelvic (1 man) involvement by myelomatous masses penetrating into surrounding tissues. In our series, only a case of osteosclerotic bone myeloma was observed in the pelvis, associated with lytic abnormalities.

The role of CT in the diagnosis and management of MM has not been assessed, because this technique demonstrates tumor extent more accurately than radiography but CT findings do not seem to improve the clinical approach and therapeutic management of the disease. Nevertheless, we recommend CT for some myelomatous conditions, namely: a) in the patients with focal bone pain but normal skeletal radiographs; b) in the patients with M protein, bone marrow plasmocytosis and back pain, but with an inconclusive MM diagnosis; c) to assess bone spread in the regions which are anatomically complex or difficult to study with radiography and to depict soft tissue involvement; d) for bone biopsy.