Challenging Already Established Statements on the Therapy of Renal Angiomiolypoma

Abstract

Renal angiomyolipoma (AML) is a benign mesenchymal tumour that can occur sporadically in 80% of cases, and in these cases they are likely to be solitary lesions being four times more likely in women. It also occurs in tuberous sclerosis (TS) and in these cases they are likely to be multiple. Currently, with the widespread use of imaging techniques, more than 80% were diagnosed incidentally with haemorrhage at presentation accounting for less than 15% of cases [1]. However, although it could be considered the most common benign renal neoplasm, renal AML is not a subject of controversy and it is not on the front pages; probably because of its benign nature and relative prevalence. Nevertheless, its diagnosis raises questions about its management and can lead to overtreatment and/or inadequate monitoring. Nowadays, we do not have clear guidance on the management of renal AML; in fact, the guidelines we use today are based on statements that were established a long time ago. We should differentially consider AMLs associated with TS and sporadic forms. In fact we can consider both completely different diseases, since AML associated with TS notably results in important morbidity and mortality, and therefore should not be considered in the same way we consider sporadic AML [2]. Recently there is a growing interest for AML since it has been suggested that those associated with TS could be managed with mechanistic target of rapamycin inhibitors. However, although there are some trials demonstrating the efficacy of this kind of therapy in patients affected by TS, there are still too many unsolved questions regarding the duration of therapy, durability of the response, or toxicity related to long-term therapy. Furthermore, the efficacy of these therapies has not been established in the more frequent sporadic presentation of AMLs [3]. Regarding sporadic AML, historically intervention has been recommended for symptomatic AMLs > 4c m and in cases associated with large aneurysms, in those with poor access to follow-up, or women of childbearing age [3] .I n these cases, the possibility of future bleeding or the risk of assuming complications leads to a preventive attitude and intervention being considered. There are several forms of therapy, from transarterial embolization, to nephron-sparing surgery, or even radical nephrectomy. However, although size has been accepted as a prognostic factor, the biggest cut-off for deciding intervention is still under debate and clear inclusion criteria for