Spontaneous regression of adrenal metastasis from renal cell carcinoma after sunitinib withdrawal: case report and literature review

BACKGROUND: The spontaneous regression of metastatic renal cell carcinoma is a rare phenomenon, with an estimated incidence of < 1%. We report a case of post-nephrectomy renal cell carcinoma adrenal metastasis, followed by the spontaneous regression of the metastasis after withdrawal of sunitinib. CASE PRESENTATION: The patient was a 55-year-old male with clear cell type renal cell carcinoma who previously underwent a left laparoscopic radical nephrectomy. After 51 months of follow up, a recurrence in the left renal fossa was observed and subsequently excised. Four months after excision, an abdominal Computerized tomography (CT) identified an adrenal metastasis of 1.6 cm. The patient was treated with sunitinib. However, the treatment was discontinued because of gastrointestinal side effects and fatigue. Eleven months after the discontinuation of sunitinib treatment, a progression in the adrenal metastasis growth (5.7 cm) was observed, whereas 16 months after the discontinuation, a regression of the adrenal metastasis growth (3.4 cm) was observed. During subsequent follow-ups, a gradual reduction in the size of the adrenal metastasis (1.8 cm) was observed. After 44 months from the discontinuation of sunitinib treatment, the patient was still alive and followed up in the outpatient department. CONCLUSIONS: Sunitinib is a multi-targeted inhibitor of vascular endothelial growth factor (VEGF) receptors. This compound reduces tumor angiogenesis and has been approved worldwide for the treatment of advanced renal cell carcinoma. To our knowledge, this is the fourth case of the spontaneous regression of metastatic renal cell carcinoma after the discontinuation of sunitinib treatment.