[Quantitative analysis of bone density in multiple myeloma].

Bone lesions are the main sign of neoplastic proliferation of multiple myeloma (MM), a disseminated malignant disease which originates in, invades and replaces normal bone marrow. The most characteristic radiographic pattern is a focal lytic lesion, well-defined or "punched-out", generally with no surrounding bone reaction. The association is confirmed between MM and osteoporosis, as reduced bone density (osteopenia) and pathologic fractures (ribs, spine). This paper is aimed at evaluating the importance of osteopenia in both diagnosis and prognosis of MM. Eighteen patients affected with MM were examined with quantitative computed tomography (QCT) and dual-energy X-ray absorptiometry (DEXA) for bone densitometry in lumbar spine and proximal femur. The patients (12 males and 6 females) were classified according to Durie's clinical criteria and to the radiographic patterns suggested by Merlini. The results indicate the patients with an advanced clinical stage (III) and scintigraphic expansion of bone marrow to have low densitometric values on both QCT and DEXA. There was substantial agreement between the 2 methods, but DEXA had a higher number of false positives. Instrumental diagnostic protocol may be thus planned as follows: 1) conventional radiography; 2) bone marrow scintigraphy; 3) bone densitometry of lumbar spine, with QCT. The patient is then to be followed with conventional and/or digital radiography in symptomatic locations, and with bone scintigraphy.