Bilateral kidney metastases from adenoid cystic carcinoma of lung: a case report and literature review.

Adenoid cystic carcinoma (ACC) is a rare malignant tumor, usually arising from salivary glands and rarely found in other locations. ACC is characterized by asymptomatic course, slow growth pattern, perineural invasion and high incidence of late metastasis. Renal localization of metastasis is rare. Only 12 cases of renal metastasis were published and, to our best knowledge, no case of bilateral metastasis to the kidney has ever been reported. We present a case of a 58 years old woman with bilateral renal metastasis from ACC of the right lung after fourteen years from lobectomy and radiotherapy for the primary presentation. The patient underwent bilateral robot-assisted partial nephrectomy in a two-stage approach. Despite its rare incidence and slow growth, ACC metastasis may simulate primary papillary renal carcinoma and occur many years after primary treatment. Therefore, lifelong follow-up, including abdominal imaging, is recommended.