Musculoskeletal · Case 07

Superscan secondary to diffuse mottled uptake in the bones

Imaging Findings

Diffuse osteoblastic metastases from prostate cancer, including the entire axial skeleton and proximal appendicular skeleton. Renal and bladder activity cannot be appreciated, due to the metastasis accumulating most of the radionuclide resulting in a higher number of counts than normal from the bones. If the images are appropriately windowed the kidneys will be visualized.

Essential Facts

Prostate cancer is one of the most common types of cancers in men. Common symptoms include trouble urinating, pelvic discomfort, and erectile dysfunction. While prostate cancer can be indolent, certain types are aggressive and quickly spread.
Bone is the second most common site of metastatic disease, and indicates a poor prognosis.
Detecting and understanding characteristics of the extent of metastatic bone disease is important for appropriate staging and restaging. 
“Superscan” is when there is  minimal to no renal activity identified secondary to diffuse uptake in the bone metastasis.  Careful attention to heterogeneity of the bones which may indicate subtle diffuse metastasis.

Scan Information

Bone scans with labeled phosphonates allow for the visualization of local bone metabolism, which is activated in the earlier phases of many types of malignancies. This allows for the use of bone scans to detect metastases when they are associated with marked reactive hypermetabolism of bone, seen in metastases from breast cancer, prostate cancer, neuroendocrine tumors. Contrastingly, bone scans are not useful in detecting metastases from cancers that cause bone-marrow proliferation (lymphoma). It is important to recognize that bone matrix regeneration after treatment of bone metastases can induce metabolic activation, making it possible to misinterpret the imagining as disease progression. A normal bone scan is displayed below to contrast from abnormal bone scans.

References

https://drive.google.com/drive/folders/1pEEBm7ePE6APW–94IDH-ggpLzFWiRTz
Nuclear Medicine Case Review Series, by Harvey A. Ziessman, Elsevier, 2011, p. 143-144.
Pauwels, E K, and M P Stokkel. “Radiopharmaceuticals for Bone Lesions. Imaging and Therapy in Clinical Practice.” The Quarterly Journal of Nuclear Medicine : Official Publication of the Italian Association of Nuclear Medicine (AIMN) [and] the International Association of Radiopharmacology (IAR), U.S. National Library of Medicine, Mar. 2001, www.ncbi.nlm.nih.gov/pubmed/11456371
Adams, Chad. “Bone Scan.” StatPearls [Internet]., U.S. National Library of Medicine, 8 Feb. 2019, www.ncbi.nlm.nih.gov/books/NBK531486/.