Abstract
Prostate cancer osteoblastic metastases may have different morphologies, and some of these may overlap with certain benign bone lesions. In this series of 5 prostate cancer patients, we describe bone lesions with central lucency and surrounding peripheral sclerosis, and their varying appearances on different imaging modalities. Although prostate cancer metastases are commonly associated with sclerotic lesions, they can also present as osteolytic or lucent lesions and these lesions should be carefully evaluated. The findings emphasize the importance of correlation with prior imaging, comparing findings on different imaging techniques and follow-up to differentiate benign disease from metastatic disease in these situations.
Keywords: Prostate Cancer, Osseous Metastases, 68Ga-PSMA, PET/CT, Bone scan, 18F-Fluciclovine, Ring sclerosis
Figure 1.
68Ga-PSMA PET/CT and bone scintigraphy images of a 53-year-old man with prostate adenocarcinoma. Axial CT (A) and axial fused 68Ga-PSMA PET/CT (B) images show focal uptake (SUVmax 5.5) corresponding to a lesion with a sclerotic ring involving the left 10th rib (white arrows). Posterior planar (D), axial CT (E), axial fused SPECT/CT (F) images of a bone scintigraphy study performed approximately 12 months prior demonstrates focal uptake of radiotracer uptake (white arrows) and compatible with a benign osseous fibrous dysplasia. 68Ga-PSMA uptake in benign bone lesions such as fibrous dysplasia has been described in patients undergoing studies for prostate cancer evaluation[1–4].
Figure 2.
Staging 18F-Fluciclovine PET/CT images of a 60-year-old man with prostate adenocarcinoma. Axial CT (A) and axial fused 18F-fluciclovine PET/CT (B) demonstrates focal radiotracer uptake (SUVmax 2.7) with a lesion in the left anterior superior iliac spine which demonstrates peripheral ring sclerosis (white arrows). Axial CT (C) and axial fused 18F-fluciclovine PET/CT (D) performed 2 years later demonstrates increase in the associated sclerosis and radiotracer activity (SUVmax 4.0) (black arrows) with rising serum PSA compatible with metastasis. Although prostate cancer osseous metastases are commonly associated with sclerotic lesions, they can also present as lucent lesions[5].
Figure 3.
74-year-old man with prostate adenocarcinoma. Axial fused 68Ga-PSMA PET/CT image (A) and axial CT image (B) demonstrates focal uptake (SUVmax 3.1) within a lesion demonstrating ‘ring sclerosis’ in the right 10th rib (white arrows). The axial fused 18F-fluciclovine PET/CT (C) demonstrates no significant radiotracer uptake greater than the background marrow uptake. Axial CT (D) of a cardiac CT examination performed approximately 3 years prior to the PET/CT studies demonstrates the lesion, confirming benignity.
Figure 4.
60-year-old man with biochemically recurrent prostate adenocarcinoma. Axial CT (A), axial fused 18F-fluciclovine PET/CT (B) demonstrates a lucent lesion with peripheral rim sclerosis in the left superior pubic ramus with increased radiotracer activity (SUVmax 4.8) (white arrows). Axial CT image (C) of a CT examination performed approximately 3 years later on ADT demonstrates increased sclerosis of the same lesion characteristic for healing bone metastasis. Prostate metastases demonstrate significant avidity on 18F-fluciclovine and 68Ga-PSMA imaging, and progressive increase in radiotracer uptake or treatment related changes may help in differentiating metastasis from benign disease[6,7].
Figure 5.
65-year-old man with prostate adenocarcinoma. Axial CT (A), axial fused 18F-fluciclovine PET/CT (B) demonstrates a lucent lesion with peripheral rim sclerosis in the right iliac crest with mild increased radiotracer activity (SUVmax 2.8) (white arrows). Axial CT (C), axial fused 99mTc-MDP SPECT/CT (D) examination performed 6 months prior demonstrates identical morphology of the lesion with mild focal radiotracer activity (black arrows). Patient was treated with salvage radiotherapy to the prostate bed only and achieved undetectable PSA, proving benignity. 18F-fluciclovine uptake in fibrous dysplasia has not been investigated. 18F-fluciclovine uptake has been observed in benign osseous disease such as osteoid osteoma, musculoskeletal inflammation, among others[8].
Abbreviations:
- 18F
fluorine-18
- PSMA
prostate specific membrane antigen
- 68Ga
gallium-68
- WBS
whole body scintigraphy
- PET/CT
positron emission tomography/computed tomography
- SUV
standardized uptake value
References
- 1.De Coster L, Sciot R, Everaerts W, et al. Fibrous dysplasia mimicking bone metastasis on 68GA-PSMA PET/MRI. Eur J Nucl Med Mol Imaging [Internet]. 2017;44:1607–1608. Available from: http://link.springer.com/10.1007/s00259-017-3712-6 [DOI] [PubMed] [Google Scholar]
- 2.Reale ML, Buttigliero C, Tucci M, et al. 68Ga-PSMA Uptake in Fibrous Dysplasia. Clin Nucl Med [Internet]. 2019;44:e396–e397. Available from: http://journals.lww.com/00003072-201906000-00031 [DOI] [PubMed] [Google Scholar]
- 3.Keidar Z, Gill R, Goshen E, et al. 68Ga-PSMA PET/CT in prostate cancer patients – patterns of disease, benign findings and pitfalls. Cancer Imaging [Internet]. 2018;18:39. Available from: https://cancerimagingjournal.biomedcentral.com/articles/10.1186/s40644-018-0175-3 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 4.Kransdorf MJ, Moser RP, Gilkey FW. Fibrous dysplasia. RadioGraphics [Internet]. 1990;10:519–537. Available from: http://pubs.rsna.org/doi/10.1148/radiographics.10.3.2188311 [DOI] [PubMed] [Google Scholar]
- 5.Beheshti M, Vali R, Waldenberger P, et al. The Use of F-18 Choline PET in the Assessment of Bone Metastases in Prostate Cancer: Correlation with Morphological Changes on CT . Mol Imaging Biol [Internet]. 2010;12:98–107. Available from: http://link.springer.com/10.1007/s11307-009-0239-7 [DOI] [PubMed] [Google Scholar]
- 6.Pomykala KL, Czernin J, Grogan TR, et al. Total-Body 68 Ga-PSMA-11 PET/CT for Bone Metastasis Detection in Prostate Cancer Patients: Potential Impact on Bone Scan Guidelines. J Nucl Med [Internet]. 2020;61:405–411. Available from: http://jnm.snmjournals.org/lookup/doi/10.2967/jnumed.119.230318 [DOI] [PMC free article] [PubMed] [Google Scholar]
- 7.Chen B, Wei P, Macapinlac HA, et al. Comparison of 18F-Fluciclovine PET/CT and 99mTc-MDP bone scan in detection of bone metastasis in prostate cancer. Nucl Med Commun [Internet]. 2019;40:940–946. Available from: http://journals.lww.com/00006231-201909000-00010 [DOI] [PubMed] [Google Scholar]
- 8.Schuster DM, Nanni C, Fanti S, et al. Anti-1-Amino-3–18F-Fluorocyclobutane-1-Carboxylic Acid: Physiologic Uptake Patterns, Incidental Findings, and Variants That May Simulate Disease. J Nucl Med [Internet]. 2014;55:1986–1992. Available from: http://jnm.snmjournals.org/cgi/doi/10.2967/jnumed.114.143628 [DOI] [PMC free article] [PubMed] [Google Scholar]