Renal cell carcinoma with acrometastasis: report of two cases and review of the literature.

Metastases to the small bones of the hands and feet are rare. Although acrometastasis is usually a late manifestation of disseminated disease, it may be the primary manifestation of an occult carcinoma. Clinically it may be confused with benign disease and be treated improperly. We report two cases of renal cell carcinoma metastatic to the distal phalanx of a finger in Case 1 and the proximal phalanx of a toe in Case 2. The lesion was discovered following trauma in Case 1. In Case 2 there was no history of trauma. These acrometastases were the first evidence of metastatic disease in these two patients who had undergone a nephrectomy for Stage II renal cell carcinoma 2 yr and 1 yr prior to the development of acrometastases, respectively. Additional visceral metastases developed over the following months in Case 1, and the patient expired 7 mo after the discovery of the acrometastasis. In Case 2, the acrometastasis was the only site of metastases, and the patient is alive and well without evidence of disease as of the latest follow-up in January 1990. Review of the literature, including our cases, revealed 22 cases of renal cell carcinoma metastatic to the bones of the hand, nine cases to the bones of the foot, and three cases to the bones of both hand and foot. The clinical characteristics, pathogenetic mechanisms, and treatment are reviewed.