Microwave Ablation of Renal Angiomyolipoma

Fig. 18.1

Ultrasound-guided percutaneous microwave ablation (MWA) in a 55-year-old female patient with angiomyolipoma in the upper pole of the right kidney. (a ) The lesion is hyperechoic and with well-defined borders in ultrasound (arrow). (b) The lesion showed heterogeneous hypo-enhancement in the arterial phase of contrast-enhanced ultrasound and the dimension is 5.7 × 5.4 cm (arrows). (c) After ablation, the lesion showed no enhancement in the arterial phase with contrast-enhanced MRI in transversal scan (arrows). (d) After ablation, the lesion showed no enhancement in the delayed phase with contrast-enhanced MRI in coronal scan (arrows). The significance of 1 and 2 in the Fig. 18.1 (a) and (b) is the two perpendicular diameters

Table 18.1

Basic characteristics and clinical results of patients with renal AMLs treated with ablation

Author	No. of Pts (nodules)	Size (cm)	Treatment type	Guided methods	Follow-up (months)	Results (no. of recurrence/persistence)	Major complications (patients)
Sooriakumaran et al. [26]	4 (4)	9.5 (9–19)	RFA	N/A	9 (2–13)	0/4	0
Gregory et al. [27]	4 (4)	15.1 (6.1–32.4)	RFA	CT	48	0/4	0
Prevoo et al. [28]	1 (1)	4.5	RFA	CT	12	1/0	0
Castle et al. [29]	15 (15)	2.6 (1.0–3.7)	RFA	Laparoscopic (5) or CT (10)	21.1 (1.5–72)	15/0	2
Byrd et al. [30]	6 (12)	4.2 (2.5–7.0)	Cryoablation	Laparoscopic	N/A	7/0	0
Johnson et al. [13]	3 (3)	(1.2–2.5)	Cryoablation	CT	5–36	2/1	0
Han et al. [35]	14 (19)	3.4 (0.8–6.1)	MWA	US	10 (6–36)	15/4	2

AML Angiomyolipoma, Pts patients, MWA microwave ablation, RFA radiofrequency ablation, US ultrasound, N/A not available, CT computed tomography; “no recurrence” was evaluated in the completely ablated lesions and “persistent” was evaluated in the incompletely ablated lesions

18.6 Conclusion

Because of the nonaggressive biologic behavior of these benign renal tumors, there is increasing interest in minimally invasive treatment modalities, particularly for the elderly, the infirm, and patients with comorbid conditions. MWA may be an alternative minimally invasive technique for the treatment of renal AML. However, the studies of large sample and long-term follow-up period are necessary to determine efficacy, and safety.

References

Lopez-Beltran A, Scarpelli M, Montironi R, Kirkali Z. 2004 WHO classification of the renal tumors of the adults. Eur Urol. 2006;49:798–805.PubMedCrossRef

Lopez-Beltran A, Carrasco JC, Cheng L, Scarpelli M, Kirkali Z, Montironi R. 2009 update in the classification of renal epithelial tumors in adults. Int J Urol. 2009;16:432–43.PubMedCrossRef

Prasad SR, Surabhi VR, Menias CO, Raut AA, Chintapalli KN. Benign renal neoplasms in adults: cross-sectional imaging findings. AJR. 2008;190:158–64.PubMedCrossRef

Steiner MS, Goldman SM, Fishman EK, Marshall FF. The natural history of renal angiomyolipoma. J Urol. 1993;150:1782–6.PubMed

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