Adult multilocular cystic nephroma: Report of six cases with clinical, radio-pathologic correlation and review of literature

Background: Cystic renal neoplasms of the kidney can be benign or malignant. Multicystic nephroma (MCN) represents a rare benign cystic lesion of the kidney, which usually presents as a unilateral multicystic renal mass without solid elements. According to the World Health Organization (WHO) classification of the renal neoplasms, it is grouped along with mixed epithelial-stromal tumor of the kidney. Materials and Methods: We report a retrospective review of six cases of MCN of kidney. Patient demographics, imaging findings, operative details and final histology were recorded. Results: All patients had suspicious/malignant features on radiological examination, leading to a radical nephrectomy. However, microscopically these lesions were lined by cuboidal epithelium, and in a few places hobnail epithelium. No cells with clear cytoplasm, blastemal or immature elements were seen. In one case, foci of inflammatory cells and histiocytes were present. Conclusions: MCN is a benign cystic lesion and clinical presentations are nonspecific with symptoms such as abdominal pain, hematuria and urinary tract infection. These nonspecific clinical presentations and confusing radiological features create difficult preoperative differentiation from malignant cystic renal neoplasms.