¹⁸F-Fluoride PET/CT in the detection of bone metastases in clear cell renal cell carcinoma: discordance with bone scintigraphy

Excerpt

Bone metastases are a frequent complication in patients with clear cell renal cell carcinoma (RCC). Skeletal involvement frequently shows lytic characteristics and is related to events such as pain, pathological fractures, spinal cord compression and hypercalcaemia. Bone metastases often require palliative radiation therapy and orthopaedic surgery [1, 2]. Bone scintigraphy (BS) has long been the reference technique for the detection of bony metastases, but is of limited value in aggressive osteolytic metastases and in the detection of early osteoblastic changes [3]. Instead, ¹⁸F-fluoride PET/CT seems to demonstrate be promising. We present the case of a patient with clear cell RCC who underwent BS and ¹⁸F-fluoride PET/CT to restage the disease after nephrectomy. BS showed increased uptake of the tracer in D8 and, faintly, in the left scapula and left anterior iliac spine (a, arrows). PET/CT (b) demonstrated multiple pathological bone lesions including the scapula (c and d, arrows), sternum, right rib, vertebra (e and f, arrows), and pelvis (g and h, arrows). The majority of the lesions had a lytic structure; the others were mixed. The extensive lytic lesions in the scapula and pelvis were much more clearly seen on PET/CT than the faint uptake seen on BS. In addition PET/CT showed three areas of abnormal uptake: D4, D8 (e and f, arrows), and pubis. These areas showed no significant alterations on CT images. Considering the evident limitations of BS,¹⁸F-fluoride PET/CT could represent a primary approach in the detection of bone lesions in patients with clear cell RCC.

…