Taken together, unfortunately, these limitations drasti- cally weaken conclusions from this study. One can conclude that both NSS and RN lead to durable cancer control. Whether NSS and RN are equivalent with regard to OS needs further investigation. We caution readers to conclude that RN is acceptable in cases where NSS is feasible. NSS is and remains the gold standard therapy for small renal masses. We want to congratulate the authors for undertaking a surgical trial, as these trials are notoriously difficult in terms of enrollment and adherence. Conflicts of interest: The authors have nothing to disclose. Reference [1] MacLennan S, Imamura M, Lapitan MC, et al. Systematic review of oncological outcomes following surgical management of localised renal cancer. Eur Urol 2012;61:972–93, 2012;62:193 [corrigendum]. Luis A. Kluth, Evanguelos Xylinas, Shahrokh F. Shariat* Weill Medical College of Cornell University, New York, NY, USA *Corresponding author. E-mail address: sfshariat@gmail.com (S.F. Shariat). http://dx.doi.org/10.1016/j.eururo.2012.11.016 Re: Multilocular Cystic Renal Cell Carcinoma with Focus on Clinical and Pathobiological Aspects Kuroda N, Ohe C, Mikami S, et al. Histol Histopathol 2012;27:969–74 Experts’ summary: Multilocular cystic renal cell carcinoma (MCRCC) accounts for approximately 1–2% of all renal tumors. This tumor, classified as a subtype of clear cell renal cell carcinoma (RCC), generally exhibits a low Fuhrman nuclear grade and low-stage TNM classification. The great majority of these tumors have a favorable clinical course. Experts’ comments: This publication leads us to make some reflections on termi- nology, in particular on whether we should continue to call MCRCC carcinoma when the World Health Organization (WHO) definition is adopted for this type of tumor. Macroscopically, MCRCC consists exclusively of variably sized cysts that are separated by thin septa (Fig. 1) and filled with clear, serous, or gelatinous fluid or, much less frequently, with hemorrhagic debris. Solid, grossly discern- ible tumor mural nodules are incompatible with the diagnosis [1–4]. The gross morphology closely reflects the imaging findings. For instance, ultrasonography reveals a well-defined multilocular cystic mass composed of serous or complicated fluid. Computed tomography scan without enhancement discloses that MCRCC consists of separated and variably sized cysts showing hypodensity and is separated from the nontumorous renal parenchyma by a fibrous capsule. According to Bosniak classification, most cases with MCRCC correspond to category 2 or 3, but even category 4 may occur in some cases. Microscopically, the cysts are lined with a single layer of tumor cells with abundant clear cytoplasm and small nuclei without nucleoli (Fuhrman nuclear grade I). The septa separating the cysts consist of fibrous tissue. An important diagnostic feature, seen in almost all cases, is the presence within the fibrous septa of clusters of tumor cells similar to those lining the cysts (Fig. 1, insert). Vascular invasion and sarcomatous transformation have not been reported [1–4]. The differential diagnoses mainly include benign multi- locular renal cortical cysts and clear cell RCC with cystic necrosis. Simple cortical cysts constitute the most common renal cysts, with a reported incidence >27% on radiologic evaluation in individuals >50 yr of age. The cysts are usually unilocular, oval to round with a smooth outline, and lined by a single layer of flattened to cuboidal epithelium, often filled with transudate-like clear or straw-colored fluid. Infrequent- ly, such cysts may be multilocular and demonstrate radiologic complexity, which may raise the possibility of a cystic neoplasm and lead to surgical resection. The lining epithelium in these unilocular or multilocular cysts occa- sionally shows more complex architectural patterns. The lining in some cysts displays papillary proliferation compris- ing cuboidal, hobnail cells with either eosinophilic or basophilic cytoplasm; in others, the lining may be composed [(Fig._1)TD$FIG] Fig. 1 – Whole-mount section of a multilocular cystic renal cell carcinoma composed of variably sized cysts separated by thin septa; (insert) microscopically, the cysts are lined by a single layer of tumor cells with abundant clear cytoplasm and small nuclei without nucleoli (Fuhrman nuclear grade I). An important diagnostic feature is the presence within the fibrous septa of clusters of tumor cells similar to those lining the cysts. EUROPEAN UROLOGY 63 (2013) 399–403 400