Diffuse renal retention on bone scintigraphy in localized clear-cell renal epithelial neoplasm.

Bone scintigraphy performed to assess the significance of an incidental finding of a small sclerotic rib lesion on a chest radiograph of a patient with no known malignancy demonstrated no evidence of metastatic disease, but there was moderate diffuse parenchymal retention in the left kidney. Renal ultrasound revealed an ovoid, slightly hyperechoic mass in the inferior pole of the left kidney, and subsequent contrast CT demonstrated a well-circumscribed hypervascular mass in that location. At nephrectomy, a localized 1.5-cm diameter clear-cell epithelial neoplasm, not definitely malignant, was found. No other abnormalities were noted in the remainder of the left kidney or in the surrounding soft tissues. No calcifications or other parenchymal changes in the kidney were identified to explain the retention of the bone agent, which was possibly related to the hyperemia associated with the neoplasm and undefined parenchymal factors.