A case of mucinous urothelial-type adenocarcinoma of the prostate in a 68-year-old man is reported. This is a rare neoplasm which probably originates from the proximal prostatic ducts or the prostatic urethra. This tumor does not express prostate-specific antigen, in contrast to the more common mucinous adenocarcinoma of the prostate, and may be misdiagnosed as a secondary, mainly colorectal, tumor. Clinical examinations and immunohistochemistry may help in the differential diagnosis. Owing to local recurrences two transurethral resections of the prostate were performed in our patient during 3 years of follow-up. He died from this tumor 40 months after the first biopsy.

El carcinoma renal de los conductos colectores es una variante poco frecuente de carcinoma renal. Típicamente su comportamiento es más agresivo que el de otras formas de carcinoma de células renales, siendo habitualmente diagnosticado en estadios avanzados. Presentamos un caso de carcinoma renal de los conductos colectores de bajo grado. Un varón de 57 años fue admitido en nuestro hospital con clínica de cólico nefrítico. En el TAC se observó una masa en el riñón derecho y se le realizó una nefrectomía parcial. El diagnóstico histológico fue carcinoma renal de los conductos colectores de bajo grado. Es una entidad nueva, de comportamiento desconocido y aparentemente menos agresivo que el carcinoma de los conductos colectores clásico. Describimos las características clínicas, radiológicas, histológicas e inmunohistoquímicas de este tumor y revisamos la literatura. PALABRAS CLAVES: Carcinoma de los conductos colectores. Bellini. Bajo grado. Riñón.

1) This study shows that 44% of all prostate cancer express the cerbB-2 oncoprotein with immunohistochemical technique. 2) These findings suggest that is necessary to standardize the immunohistochemical staining procedure with cerbB-2 in prostate adenocarcinoma. 3) The level of cerbB-2 expression was correlated with Gleason grade and clinical stage.

Collecting duct renal cell carcinoma is an uncommon variant of renal carcinoma. Typically its behaviour is more aggressive than other forms of renal carcinoma and usually it is diagnosed at advanced stages. A 57-year-old man visited our hospital by right lumbar pain. Abdominal CT showed a enhanced mass on the right kidney. A right partial nephrectomy was done. Histological examination of the surgical specimen showed a low grade collecting duct carcinoma of the kidney. This is a new entity, with unknown behaviour but seems to be less aggressive than classical collecting duct carcinoma of the kidney. The clinical, radiological, pathological and immunohistochemical characteristics of this tumor are reported, and the literature is reviewed.