[Immunohistochemical profile and clinical features of mucinous tubular and spindle renal cell carcinoma].

INTRODUCTION We present the immunohistochemical (IHC) analyses of a series of four kidney tumors currently classified as mucinous tubular and spindle renal cell carcinoma (WHO), a tumor with uncertain histogenesis and differentiation. Our aims were to determine an immunoprofile and to add clinical and morphological information about this rare renal carcinoma. MATERIAL AND METHODS The four tumors were found between 415 renal carcinomas at our center (0.89%). IHC was carried out with a panel of antibodies in these four cases. Morphogical and clinical information was collected and analyzed. RESULTS All tumors were well circumscribed and confined to the kidney. Immunoreactivity for cytokeratin (CK)7 was intense and diffuse. Immunostaining was variable for EMA, vimentin, S-100, Ulex europaeus antigen, high-molecular-weight CK, CK 8, CK18, and CK 19. The tumors were homogeneously negative for CEA, CD15, CD10, CD34, desmin, actin, CK10, CK20, and HMB45. Proliferative index (Ki67) was <1% en all cases. The immunoreactivity was similar in cuboidal and spindle cells. CONCLUSIONS The present tumor shows a variable immunophenotype and there is not a precise cell type differentiation. The immunostaining in cuboidal and spindle cells suggests a similar differentiation and histogenesis.