Metastatic hypernephroma to the head and neck: unusual case reports and review of the literature.

Hypernephroma is one of the most common tumours to spread by extranodal metastases to the head and neck. We herein report on six patients with unusual metastatic hypernephroma to the head and neck area. In two of the six cases, the metastatic tumour in the head and neck was the presenting symptom, and the renal tumour was secondarily detected. Metastatic hypernephroma to the head and neck area has been demonstrated mostly in the paranasal sinuses, parotid gland, and the mandible. Among the six cases presented, four belong to the above-mentioned group, but the other two are rather rare cases, one metastatic to the nasopharynx and soft palate and the other to both lobes of the thyroid gland. Hypernephroma should be sought and excluded whenever a metastatic lesion is encountered in the head and neck area, even if the metastatic lesion is the first clinical presentation. The diagnosis of metastatic hypernephroma should be suspected in any patient with even a remote history of renal cell carcinoma.