Huge renal cyst with parietal renal cell carcinoma, osseous metaplasia and a papillary adenoma: a case report with unique clinicopathological features and literature review.

The unique clinicopathological features of a giant solitary renal cyst with a parietal clear cell carcinoma in contiguity with a focus of osseous metaplasia and a papillary adenoma are reported. Ultrasonography and computed tomography showed a single cyst with a focal wall irregularity. During surgery, a frozen section revealed the presence of a renal cell carcinoma of clear cell type, so a nephrectomy was performed. After extensive pathological sampling of the cyst's wall, a focus of osseous metaplasia in contiguity with the main tumour and a microscopic papillary adenoma were found. Diagnostic implications for the present case are discussed within a pertinent literature review.