Percutaneous ablation of adrenal tumors

Abstract

Adrenal tumors comprise a broad spectrum of benign and malignant neoplasms and include functional adrenal adenomas, pheochromocytomas, primary adrenocortical carcinoma, and adrenal metastases. Percutaneous ablative approaches that have been described and used in the treatment of adrenal tumors include percutaneous radiofrequency ablation, cryoablation, microwave ablation, and chemical ablation. Local tumor ablation in the adrenal gland presents unique challenges, secondary to the adrenal gland's unique anatomic and physiological features. The results of clinical series employing percutaneous ablative techniques in the treatment of adrenal tumors are reviewed in this article. Clinical and technical considerations unique to ablation in the adrenal gland are presented, including approaches commonly used in our practices, and risks and potential complications are discussed.

Figure 1

(a–c): 65 year old patient with painful left adrenocortical cancer recurrence in the left adrenalectomy bed. (a): Axial contrast enhanced CT demonstrates a 4.5 cm mass in the left adrenalectomy bed (white arrow), medial to the spleen. (b) RFA was performed in the prone position. (d) Contrast-enhanced CT obtained 12 months after ablation shows a reduction of the mass (white arrow) and no evidence for residual enhancement. Patient’s pain resolved after RFA. Treating the splenic tail is usually well tolerated.

Figure 2

(a–h). Cryoabation of a painful renal cell carcinoma metastasis to the right adrenal gland. (a,b): Non-contrast CT demonstrates a large heterogeneous right adrenal mass (arrow). (c,d): Cryoablation of patient’s right adrenal mass was performed with 6 cryoprobes using a 10 minute freeze, 8 minute thaw, and 10 minute freeze cycles. (e–h): 3 month follow up contrast-enhanced CT shows the non-enhancing ablation zone (small paired white arrows) and a residual focus of linear enhancement along the lateral margin of the ablation zone (long white arrows) consistent with residual tumor. The patient’s pain improved significantly following the ablation.

Figure 3

(a–j). 65 year old man with stage IIIA non-small cell carcinoma treated with chemotherapy and radiation therapy with a solitary right adrenal metastasis, which remained the sole disease site for one year. (a–d): Pre-ablation CT (a,b) and PET-CT (c,d) demonstrate an FDG avid cystic 6 × 4 cm cystic right adrenal mass (a,b: white arrows; c,d: black arrows). Biopsy was consistent with metastatic non-small cell carcinoma. Microwave ablation was chosen given the size and cystic nature of tumor. (e–f): Three 3.7-cm active tip microwave antennae were inserted to cover the mass (Evident, Covidien, Boulder, CO). A 10 minute treatment was performed at 45 watts. (g–h): One month follow-up contrast-enhanced CT shows a decrease in size of the ablation zone and no enhancement (white arrows). (i–j): 8 month follow up PET/CT demonstrates complete metabolic response and further decrease in size of the ablation zone (white arrows).