Hereditary Renal Tumor Syndromes and the Use of mTOR Inhibitors

The Case A 47-year-old woman with a history of drug-resistant epilepsy during childhood presented to the emergency department with sudden dyspnea and chest pain. Upon admission, her oxygen saturation was 88%. A chest CT scan revealed pulmonary cystic lesions consistent with lymphangioleiomyomatosis and a right spontaneous pneumothorax, which resolved with the placement of a chest tube. Physical examination revealed a hypopigmented macule on the skin of the lumbar region, facial angiofibromas, and periungual fibromas. An abdominal MRI documented multiple bilateral renal tumors that were hypointense on T2-weighted imaging and showed a black boundary artifact, suggestive of fat-poor angiomyolipomas (AMLs). Subsequent percutaneous biopsy of the largest renal tumor confirmed the diagnosis of angiomyolipoma (positive for HMB-45 on immunohistochemistry). The brain MRI revealed subependymal nodules. The pulmonary function tests showed a mild obstructive pattern. Germline genetic testing confirmed the suspected diagnosis, and the patient started oral systemic treatment with everolimus (Afinitor) 10 mg once daily, along with dexamethasone rinses for prophylaxis.