Advanced sporadic renal epithelioid angiomyolipoma: case report of an extraordinary response to sirolimus linked to TSC2 mutation

Marta Espinosa,Cristina Rodriguez-Antona,Alberto Cascón,Carmen Garrigos,Ignacio Duran,Mercedes Robledo,María Apellaniz-Ruiz,Juan Maria Roldán-Romero,Enrique De Álava

doi:10.1186/s12885-018-4467-6

Abstract

BackgroundRenal epithelioid angiomyolipomas (EAML) are rare tumors with aggressive behavior. EAML can be sporadic or develop within the tuberous sclerosis complex syndrome, where mutations of TSC1 or TSC2 genes (critical negative regulators of mTOR Complex 1) result in an increased activation of mTOR pathway. Optimal EAML treatment, including mTOR inhibitors, remains undetermined.Case presentationHere we present the case of a young adult with a renal EAML that after radical nephrectomy developed metastases, first in liver and then in lumbar vertebrae. After complete surgical resection of these lesions, liver recurrence was detected, this time with incomplete surgical resection. After finding a new liver lesion, systemic treatment with sirolimus started. The patient exhibited a complete and durable response to this drug, being disease free at the time of publication, after 36 months of treatment. Targeted next generation sequencing (NGS) of MTOR, TSC1 and TSC2 genes in the primary tumor, metastasis and blood of the patient, revealed one inactivating TSC2 mutation (c.2739dup; p.K914*) in the tumor cells. Immunohistochemistry revealed decreased TSC2 protein content and increased phospho-S6 in the tumor cells, demonstrating mTOR pathway activation.ConclusionNGS on an EAML patient with an extraordinary response to sirolimus uncovered TSC2 inactivation as the mechanism for the response. This study supports NGS as a useful tool to identify patients sensitive to mTOR inhibitors and supports the treatment of malignant EAML with these drugs.

Highlights

Renal epithelioid angiomyolipomas (EAML) are rare tumors with aggressive behavior
Significant clinical response to mammalian target of rapamycin (mTOR) inhibitors has been described in patients with unresectable or recurrent Perivascular epithelioid cell tumor (PEComas), specific data regarding EAML is scarce [11, 12]
Discussion and conclusions mTOR signaling pathway is up-regulated in many cancers and hamartoma syndromes through mutations in genes that participate in this pathway

Summary

Introduction

Renal epithelioid angiomyolipomas (EAML) are rare tumors with aggressive behavior. EAML can be sporadic or develop within the tuberous sclerosis complex syndrome, where mutations of TSC1 or TSC2 genes (critical negative regulators of mTOR Complex 1) result in an increased activation of mTOR pathway. Conclusion: NGS on an EAML patient with an extraordinary response to sirolimus uncovered TSC2 inactivation as the mechanism for the response. This study supports NGS as a useful tool to identify patients sensitive to mTOR inhibitors and supports the treatment of malignant EAML with these drugs.

Results

Conclusion