IS Case 230: Neuroblastoma
Imaging Sciences URMC 2008
Publication Date: 2009-05-22
Patient is a 4-year-old male with left-sided hip pain for several weeks.
Multiple Tc99m-MDP bone scan images demonstrate an area of increased radiotracer uptake superior to the left kidney, suggesting an abnormal soft tissue mass. There is no evidence of increased bone uptake in the region of the left hip. There is age-appropriate uptake at the growth plates bilaterally. The injection site is noted at the left antecubital fossa.
This case demonstrates an unusual soft tissue mass superior to the left kidney on a bone scan that was performed to assess for a bony etiology of this child’s left-sided hip pain. Further tests proved this mass to be a neuroblastoma.
While unusual soft tissue uptake may be seen on bone scan for many reasons, only some of these will be listed here. Generally speaking, it may be secondary to any process that evokes soft tissue calcification or infarction. Surface contamination must always be excluded before falsely attributing the appearance of soft tissue uptake to another etiology.
Poor kidney function will decrease radiotracer excretion and may cause a diffuse increase in soft tissue activity. Unilateral increase in activity in the area of a kidney may be due to obstruction or an extrarenal pelvis.
Some soft tissue neoplasms that may calcify and lead to soft tissue uptake include mucin-producing breast tumors, lung cancers, GI tract tumors, ovarian cancers, as well as lymphoma, osteogenic sarcoma, and neuroblastoma, as in the given case. Malignant pleural effusions or malignant ascites may also show up on a bone scan as diffusely increased uptake.
Dystrophic joint calcifications, calcific tendonitis, dermatomyositis, myositis ossificans, postoperative scars, areas of inflammation, amyloidosis and uterine fibroids are also possible causes of soft tissue uptake.
When examining a bone scan, attention must be paid not only to the bony skeleton, but also to the pattern of soft tissue uptake so as not to miss other important findings that may direct treatment or further imaging.
- Mettler FA, Guiberteau MJ. Essentials of Nuclear Imaging. 5th ed., Elsevier, Philadelphia, PA, 2006.