Bone Metastases

Bone metastases may be detected by bone scintigra-phy, MIBG scan, and PET scan. Symmetrical skeletal involvement is easier to interpret by MIBG than by bone scan. Furthermore, bone scan can remain abnormal for months even after the successful treatment of the tumor, whereas MIBG will not be taken up by healing bone; however, since bone and bone marrow are two distinct compartments with disparate prognostic importance (e.g., stage 4 vs stage 4S in infants), caution should be exercised in assigning bony involvement solely on MIBG. False-negative I-123 MIBG scans for skeletal involvement have been reported, prompting some investigators to recommend both I-123 MIBG plus bone scans for the evaluation of NB (Gordon et al. 1990). In stage-4 patients, where bony and bone marrow involvement usually go hand in hand, concordance between MIBG scanning and bone scanning is generally the rule (Shulkin et al. 1992); however, some studies have indicated that more skeletal lesions may be evident on MIBG scan compared with bone scan (Hadj-Djilani et al. 1995). Bone lesions may also be identified on CT; however, these lesions persist as abnormalities on CT for years, even in the face of bone and MIBG scans that have reverted to normal.

0 0

Post a comment