TY - JOUR AU - Abrantes, Carlos Filipe AU - Oliveira, Rui Caetano AU - Sepúlveda, Luís AU - Figueiredo, Arnaldo AU - Marinho, Carol AU - Sousa, Vítor AU - Castro, Lígia Prado e PY - 2015 TI - A case of renal cell carcinoma with abundant smooth muscle (leiomyomatous) stroma and the differential diagnosis JF - Diagnostic Pathology; 2015 DO - 10.17629/www.diagnosticpathology.eu-2015-1:28 KW - Kidney, Renal cell carcinoma, Clear cells, Leiomyomatous stroma N2 - Renal cell carcinoma with smooth muscle stroma (RCCSMS) is a rare and controversial renal cancer type with indolent behavior. This separation of this entity from other types of renal cell carcinoma is supported by recent published studies but not yet recognized by the World Health Organization. We present a case of a 72 years old female, with incidental finding on abdominal ultrasound of a renal nodule with 1.5cm. The patient underwent partial nephrectomy and the pathological evaluation showed an epithelial tumor composed of nests and trabeculae of polygonal cells with clear cytoplasm and low grade nuclear features, surrounded by an abundant stroma composed by fascicles of spindle cells without significant pleomorphism or mitoses. Immunohistochemically, the epithelial cells showed strong and diffuse positivity for CK7, CD10, vimentin and EMA; staining for RCC was focal. The stromal cells were positive for vimentin, smooth muscle actin, HHF35, desmin and caldesmon; ER and PR were negative. The staining for HMB45 and Melan-A was negative in both components. So the final diagnosis of RCCSMS was made. It’s important to be aware of this entity in order to differentiate RCCSMS from renal cancers with less favorable prognosis and higher degree of malignancy, like clear cell renal cell carcinoma, especially with sarcomatoid change. UR - https://www.diagnosticpathology.eu/content/index.php/dpath/article/view/28