The presence of two or more primary tumours is a relatively uncommon phenomenon. Recently with the improvement of diagnostic modalities, such cases are increasingly reported in the literature. This paper presents a rare case of synchronous breast and renal tumour with unusual features including RCC metastasis to the duodenum and stomach, rapid recurrence of the tumour at the nephrectomy site, rapid renal cell carcinoma growth rate and the rare presence of syncytial-type giant cells in the renal cell tumour.