Metastatic renal clear cell carcinoma of the jaws. Two cases illustrating clinical and pathological diagnostic problems.

Two cases of metastatic renal clear cell carcinomas of the mandible are presented in which the jaw symptoms preceded the discovery of the primary lesions. Their presentation mimicked vascular abnormalities both clinically and on special investigations and both required biopsy, one of which was a major excision, for diagnosis. The histological differential diagnosis of metastatic renal clear cell carcinoma from other clear cell tumours arising in the orofacial tissues can also be difficult, often requiring specialised knowledge and techniques. These points illustrate that the differential diagnosis of a pulsatile soft tissue jaw tumour developing below intact mucosa and eroding bone, should include metastatic tumour as well as vascular anomaly, vasoformative tumour, extra nodal lymphoma and primary bone tumour.