Metastatic clear cell papillary renal cell carcinoma: first case report of a previously indolent entity

Abstract

Aims Clear cell papillary renal cell carcinoma is a recently characterised low grade neoplasm which has not yet been documented to have metastasised. We report a case of clear cell papillary renal cell carcinoma with histologically proven lymph node metastasis. Method H&E sections were reviewed by two experienced uro-pathologists. Immunostaining of both the primary tumour and the lymph node metastases was performed. Results Examination of the radical nephrectomy specimen showed an 85 mm cystic tumour which was grossly organ con-fined. Histologically the tumour was characterised by areas of well developed delicate papillary structures lined by clear cells with reverse polarisation and low-grade nuclear features. Areas of nested and tubular architecture were also present. The tumour invaded into hilar fat although vascular invasion was not identified. The tumour exhibited patchy although strong CK7 immunoreactivity. Metastatic renal cell carcinoma with similar histological features was identified in two paracaval lymph nodes. Discussion We present a case of metastatic clear cell papillary renal cell carcinoma, which is, to our knowledge, the first that has been described.