Three-phase skeletal scintigraphy in a solitary lytic osseous metastasis of renal cell carcinoma.

Skeletal metastases are found at post-mortems in 25% or more of patients with renal cell carcinoma (RCC). The incidence reported during life is half of this. Conventional bone scintigraphy is widely employed in the diagnosis and follow-up of many malignant conditions and is generally accepted as the most sensitive amongst the available techniques for the detection of skeletal metastases2. However, its value in patients with RCC is not clearly defined, although it has been suggested that scanning may be more sensitive than radiological survey. 3 Reddy and Merrick (1980) reported false negative skeletal scintigranis in 4 of 12 cases of RCC with proven skeletal metastases and suggested that a normal skeletal scintigram in a symptomatic patient with known RCC does not exclude skeletal metastases. 4 Three-phase bone scintigraphy which documents the blood flow, blood pool and the bone uptake phases has received considerable attention since its Original description by Gilday et al. 5 We describe here a case of a solitary bone metastasis presenting as a cystic lesion radiographically where the conventional delayed bone scan was negative showing a photo deficient lesion. However, the 3-phase bone scan showed a characteristic pattern which yielded valuable additional information providing a clue to the nature of the lesion.