Active targeted therapy for metastatic collecting duct carcinoma of the kidney: a case report and review of the literature.

Collecting duct carcinoma (CDC) is a rare and aggressive renal cell carcinoma (RCC) with extremely poor prognosis, which has been shown to have a poor response to several kinds of systemic therapy. Targeted agents have greatly changed the therapeutic landscape in advanced RCC. Nonetheless, patients with CDC are always excluded from the prospective trials with targeted therapies due to its rarity. We present a case of metastatic CDC that responded favorably to the multiple tyrosine kinase inhibitor, sorafenib, achieving a partial response in both lungs and retroperitoneal lymph nodes metastases. We also reviewed the limited number of reports of metastatic CDC treated with targeted agents and found that 33.33 % (4/12) of patients had favorable clinical activity. These suggest that targeted therapy should be considered for the treatment of metastatic CDC and its prospective evaluation is encouraged.