Percutaneous sclerotherapy of renal cysts with a beta-emitting radionuclide, holmium-166-chitosan complex

Abstract

Objective: To evaluate the usefulness of a beta-emitting radionuclide (holmium-166-chitosan complex) as a sclerosing agent for the treatment of renal cysts.

Materials and methods: Using 10-30 mCi of holmium-166-chitosan complex, 20 renal cysts in 17 patients (14 male and 3 female patients, ranging in age from 47 to 82 years) were treated by percutaneous sclerotherapy under ultrasonographic guidance. The volume of the cysts before and after the sclerotherapy and the percentage change in volume were calculated in order to evaluate the response to therapy, which was classified as either complete regression (invisible), nearly complete regression (< 15 volume% of initial volume), partial regression (15-50 volume%) or no regression (> 50 volume%).

Results: The follow-up period ranged from 6 to 36 months (mean 28 months). Eighteen cysts (90%) regressed completely (n=11, 55%) or near-completely (n=7, 35%). Partial regression was obtained in one patient (5%) and there was no regression in one patient (5%). No significant complications were encountered.

Conclusion: The holmium-166-chitosan complex seems to be useful as a new painless sclerosing agent for the treatment of renal cysts with no significant complications.

Fig. 1

A 57-year-old man with right flank discomfort. A. Sonography of the left kidney demonstrated a giant simple cyst. The initial volume was 172 ml. B, C. Under sonographic guidance, an 18 G puncture needle was placed in the cyst (B) and as much as possible of the cystic fluid was gently aspirated. 30 mCi of holmium-166 chitosan complex was administered at the site of the placed puncture needle (C). D. Gamma camera image (coronal anterior view) showed the focal accumulation of radioactivity without any evidence of leakage. E. On the sonogram 1 month after the procedure, the cyst was found to have decreased to a volume of 47 ml. F. The cyst disappeared at follow-up sonography 6 months after the procedure.

Fig. 2

A 76-year-old man with hematuria. A. This patient underwent renal cyst 95% ethanol sclerotherapy 2 years previously. However, a remnant cortical cyst was noted at the lower pole of the left kidney on sonography, with a calculated volume of 35 ml. B. Follow-up sonography 2 months later showed a significantly reduced cyst volume of 2 ml. C. On follow-up sonography at 14 months, the cyst was undetectable, indicating a complete regression.