Collecting duct meningeal carcinomatosis

Collecting duct carcinoma (CDC) is an aggressive primary renal neoplasm tha t represents a distinct subtype of renal cell carcinoma. Histochemical (eg, mucicarmine) and immunohistochemical leg, Ulex europaeus) studies, taken i n concert with the gross and histologic findings, allow differentiation of CDC from the conventional varieties of renal cell carcinoma in most cases. Collecting duct carcinoma generally pursues a more aggressive course than c onventional renal cell carcinoma. Metastases to regional lymph nodes, bone, adrenal glands, lung and skin have been reported in CDC. We describe the c ase of a 26-year-old man who presented with a clinical and radiologic impre ssion of multifocal meningioma. Biopsies of the meninges and extracranial s oft tissues revealed metastatic adenocarcinoma; subsequent studies suggeste d metastatic CDC. Ultrasound-guided biopsy was performed an a subsequently identified renal mass, which showed features consistent with CDC. To our kn owledge, this is the first reported case of meningeal carcinomatosis due to CDC. The diagnostic features of this tumor are discussed.