Renal Cell Carcinoma: Delayed Metachronous Metastases to Parotid and Cerebellum.

PURPOSE: The purpose of this report is to describe a rare case of delayed metachronous isolated metastases of renal cell carcinoma (RCC) to the parotid gland and the cerebellum. The metastases occurred more than a decade after treatment of the primary tumor without any other systemic involvement. In addition, the potential differential diagnosis of the parotid mass based on presentation and imaging is discussed.

MATERIALS AND METHODS: An 83-year-old man presented for evaluation and treatment of a rapidly growing mass at the right parotid region. He had a history of RCC resection 10 years before this presentation and had no evidence of persistent disease at the primary site. The diagnosis of metastatic RCC was made after fine-needle aspiration biopsy examination of the mass. The patient underwent superficial parotidectomy for resection of the tumor. Approximately 1.5 years later, he complained of loss of balance. Further investigation disclosed a cerebellar mass that at biopsy examination was found to represent RCC. He underwent stereotactic ablation of the mass. He currently remains free of disease at the primary site and the parotid and without further known brain metastases.

RESULTS: This report presents the 29th case of a solitary parotid mass consistent with metastatic RCC 10 years after successful treatment of the primary RCC. Approximately 1.5 years later, the patient presented with new-onset loss of balance. Further investigation disclosed a mass to the cerebellum consistent with metastatic RCC. This case is unique because the brain involvement occurred extremely late, 11.5 years after successful treatment of primary RCC and 1.5 years after resection of a metastatic RCC to the parotid, and without any evidence of other metastases.

CONCLUSIONS: Late distant metastases of RCC are not uncommon and patients require life surveillance follow-up, but such late presentation of metachronous metastases without systemic disease progression is unique. The patterns of metastases of RCC are not clearly defined and this diagnosis should be considered, especially in patients with relevant history.