Carcinomas renales con rasgos sarcomatoides y rabdoides: estudio clínico-patológico de 74 casos / Renal cell carcinoma with sarcomatoid and rhabdoid features: a clinico-pathological series of 74 cases

RESUMEN

Fundamento Nuestro objetivo fue comparar las variables clínico-patológicas de los carcinomas renales (CCR) con fenotipos sarcomatoide y rabdoide. Material y métodos: Se revisaron 1.258 CCR de pacientes consecutivos nefrectomizados entre 1988 y 2015, y se seleccionaron aquellos con ≥1% de cambio sarcomatoide y/o rabdoide. Se clasificaron como sarcomatoide o rabdoide según el fenotipo predominante, considerándose componente desdiferenciado la suma del porcentaje de ambos. Se recopilaron sexo y edad de los pacientes, síntomas y existencia de metástasis al diagnóstico, parámetros del protocolo de CCR del Colegio Americano de Patólogos, patrón de crecimiento tumoral, invasión perineural, porcentaje de necrosis tumoral y características del infiltrado inflamatorio. Se describieron mediante la media/mediana o el porcentaje y se compararon mediante t de Student/U de Mann-Whitney o χ2/F de Fisher. Resultados: Se identificaron 45 CCR con predominio sarcomatoide (3,6%) y 29 con rabdoide (2,3%); los primeros mostraron mayor componente indiferenciado e invasión perineural respecto a los CCR con rasgos rabdoides (27,5 vs. 13,5%; p=0,003 y 28,9 vs. 3,4%, p=0,006, respectivamente), mientras que estos mostraron doble frecuencia de inflamación neutrofílica (44,8 vs. 22,2%, p=0,04) y surgieron más frecuentemente sobre un CCR de alto grado (55,9 vs. 90,5%, p<0,001). Conclusiones: Los CCR con fenotipos sarcomatoide y rabdoide compartieron características clínico-patológicas, excepto para componente desdiferenciado, invasión perineural, inflamación neutrofílica y origen en CCR de alto grado. Esta similitud sugiere la presencia de un mecanismo común, la transición epitelio-mesénquima, con una expresión morfológica doble que, de confirmarse, podría suponer la posibilidad de seleccionar pacientes para tratamiento o seguimiento a partir de sus características moleculares

ABSTRACT

Objetives. Our aim is to analyze and compare the clinico-pathological features in renal cell carcinomas (RCC) with sarcomatoidand rhaboid phenotype. Material and methods: We reviewed 1,258 RCC from consecutive patients with nephrectomy from 1988 to 2015, and those with ≥1% of sarcomatoid and/or rhabdoid change were selected. They were classified as sarcomatoid or rhabdoid according with the predominant morphology, considering the global frecuency of both phenotypes as dedifferentiated component. The following variables were collected sex, age, symptoms and existence of metastases at diagnosis, parameters listed in the protocol of renal carcinoma of the American College of Pathologists, pattern of tumor growth, perineural invasion, percentage of both tumor necrosis and characteristics of the inflammatory infiltrate. They were described by mean/median or percentage, and compared with Student-t/Mann-Whitney U or χ2/Fisher). Results: We identified 45 RCC with sarcomatoid predominance (3,6%) and twenty-nine with rhabdoid predominance (2,3%); the first one showed a higher dedifferentiated component and perineural invasion (27.5 vs. 13.5%, p=0.003 and 28.9 vs. 3.4%, p=0.006, respectively), while the former showed a higher proportion of neutrophilic inflammation (44.8 vs. 22.2%, p=0.04) and arose more frequently over high grade RCC (55.9 vs. 90.5%, p<0,001). Conclusions: There was overlapping of the clinico-pathological features of RCC with sarcomatoid and rhaboid phenotype, except for dedifferentiated component, perineural invasion and neutrophilic inflammation. This close relationship could be explained by a common underlying mechanism, the epithelial-mesenchymal transition, with a double morphological expression that, if confirmed, could lead to selecting patients that would benefit from follow-up or treatment depending on their molecular characteristics