HER2 blockade in metastatic collecting duct carcinoma (CDC) of the kidney: a case report.

Background: Collecting duct carcinoma of the kidney (CDC) is a rare cancer associated with bad prognosis and, at present, with no specific effective therapies.
Case Report: We report a clinical case with disseminated highgrade CDC presenting with widespread metastasis to both lungs, pelvic bones, axial skeleton, and the central nervous system (posterior fossa, both hemispheres and pituitary-hypothalamic). The primary tumor in the kidney was demonstrated (by fluorescence in situ hybridization and immunohistochemistry with Herceptest (3+ score)) to significantly overexpress HER2. Critically ill at presentation, the patient received oral capecitabine together with double HER2 blockade with both intravenous trastuzumab and oral lapatinib. His clinical response was a dramatic improvement and a progressive decline in the radiological size of all of his multiple cancer lesions.
Conclusion: Double HER2 blockade is an effective therapy in disseminated CDC even in the presence of brain metastases.