Sarcomatoid Transformation of Chromophobe Renal Cell Carcinoma: An unusual Pathology

Dear Editor, We have carefully read the response from Val-Bernal et al.,[1] and we feel sorry for any inconvenience that we may have caused. The purpose of our study[2] was to deepen the rare histologic type of renal tumor which is the chromophobe renal cancer with sarcomatoid differentiation, its mode of presentation, imaging techniques, histopathological analysis, prognostic factors, and treatment. Because it is a subject discussed in the literature but with only a few patients described, as a visual way to simplify the low incidence of this pathology, we used the results published by Bian et al.[3] on a table and added our clinical cases. With this, we reflected on the most important prognostic factors, as described in the literature, and how they affected survival. It is unquestionable that those two cases cited in Val-Bernal et al. could have enriched this table, especially because of their detailed histopathological analysis. Akhtar et al.[4] presented a left renal tumor with anaplastic spindle cells with a high mitotic rate intermingled with poorly differentiated pleomorphic tumor cells showing positivity for vimentin. In the same way, Gómez-Román et al.[5] showed a right renal mass with sheets of voluminous polygonal epithelial cells with 40% of the tumor displaying spindle-shaped and pleomorphic cells, showing epithelial cell diffuse reaction of the cytoplasm with Hale’s acid iron colloid stain and being the sarcomatoid areas reacted for vimentin. It should also be noted, as they argue in their letter, that their patient was alive 7 years after diagnosis, which is the longest survival time described in this type of patients. Nevertheless, as far as our review is concerned, we decided to focus more on the literature described in terms of prognostic factors and optimal treatment based on these than on the exact number of cases described, and that is the reason why unfortunately we did not add the case presented in 1996, which might have surely completed our series both in quantitative and qualitative terms. Please accept our apologies for any discomfort, and we hope that this will not happen again in the future as our ultimate goal is to combine the maximum knowledge with the previously described pertinent literature to manage complex patients in the best possible way. Irene De La Parra,1 Álvaro Serrano,1 Roser Vives,1 Juan Hermida,1 Luis Ignacio Diez-Valladares,2 Jerónimo Barrera,3 José Antonio Cortés,4 Pilar González-Peramato,5 Ángel Gómez,1 Jesús Moreno1