Renal cell carcinoma: diagnosis based on metastatic manifestations.

Renal cell carcinomas are notorious for their tendency to metastasize early, often before the primary tumor has become apparent. Frequently, the initial complaint is referable to a distant metastatic lesion. Metastatic lesions have been found in almost every organ or tissue of the body. When a patient with a clinically asymptomatic renal cell carcinoma has signs and symptoms referable to a localized lesion, the final diagnosis depends on histologic and cytologic evaluation of a biopsy specimen. In this article, we describe a patient who had a pulsating transcalvarial occipital-suboccipital mass as the initial manifestation of an occult renal cell carcinoma. Initial manifestations by site of metastasis described in the literature are reviewed, and the differential diagnosis of primary clear cell tumor versus metastatic lesions from a renal cell carcinoma, according to their pathologic features, is discussed.