[Sonographic diagnosis of metastatic renal cell carcinoma to the head and neck region].

In the area of the head and neck metastases from distant primary tumours are rare in comparison to the common squamous cell carcinomas of the upper respiratory and digestive tract. Thus correct preoperative diagnosis may be difficult. Two cases with distant metastases of renal cell carcinoma to the head and neck region are presented in this report. In a 60-year-old male patient, diagnostic evaluation of unilateral epistaxis revealed a radioopacity of the maxillary sinus, six months after removal of a renal cell carcinoma. In the second case a slowly progressive indolent swelling of the left neck developed in a 56-year-old man six years after resection of a renal cell carcinoma and two years after surgical treatment of a pancreatic carcinoma. Following clinical examination, modern imaging techniques with special emphasis on colour Doppler sonography with a Siemens Quantum 2000 were used for diagnostic evaluation in both patients. Sonography of metastatic renal cell carcinoma to the maxillary sinus revealed complete opacity of the antrum. The cervical mass proved to the inhomogeneous and hypoechogenic and was difficult to distinguish from the lower parotid lobe and the vessel sheath. A common feature of both tumours was a high degree of perfusion which could be confirmed by superselective angiography. The histological examination of the surgical specimen showed an isolated metastasis of a renal cell carcinoma in both cases. In patients with a history of renal cell carcinoma the possibility of distant spread to the head and neck region should be taken into account even after a long period of complete remission. Colour Doppler sonography facilitates the distinction between the normally well perfused secondary tumours and squamous cell carcinomas which usually only have a minimal blood supply. Because of the high risk of profuse bleeding a biopsy should only be performed in the operating theatre.