Chromophobe renal cell carcinoma with neuroendocrine differentiation.

Chromophobe renal cell carcinoma was described by Thoenes et al. in 1986, and associations with carcinoma of collecting ducts, conventional renal cell carcinoma and sarcomatoid renal cell carcinoma have been described. We report a case of chromophobe renal cell carcinoma which showed neuroendocrine differentiation. This is the first known case to be clearly identified as such. The patient was a 56-year-old man with constant right flank pain and hematuria; CT scan revealed an 8.5 cm nonhomogeneous mass involving the right kidney. Right radical nephrectomy was performed. The tumor showed a mixture of classical and eosinophilic patterns of chromophobe cell carcinoma. Additionally, it showed insular, glandular and rosetoid-like formations embedded in a dense eosinophilic hyaline stroma. The cells were cuboid or cylindrical with well-defined boundaries, finely stippled chromatin and a small nucleolus. The appearance of the cytoplasm varied from faintly eosinophilic to coarsely granular eosinophilic. Immunohistochemically, the neuroendocrine areas were reactive for C-kit, epithelial membrane antigen, cytokeratin, cytokeratin 7, chromogranin A, neuron-specific enolase, CD56 and S-100 protein. Our case represents a typical chromophobe carcinoma with neuroendocrine differentiation. Additionally, the immunohistochemical profile in both types of lesion suggests a common origin from renal tubular cells.

Basaloid carcinoma of the prostate gland. An unusual finding.

OBJECTIVES: Carcinoma with basaloid features, known as basaloid carcinoma of prostate, is an extremely rare tumor. We report the clinical, histological and immunohistochemical findings in a case of prostatic basaloid carcinoma. METHODS/RESULTS: A 68-year old man consulted with a two-year history of increasing urinary outflow obstruction that developed into acute urinary retention. A routine suprapubic prostatectomy was carried out, following which normal voiding was achieved. Microscopically, the neoplasm showed different histological aspects; some areas were typical of basal cell hyperplasia, intermixed with other in which there was evidence of basaloid carcinoma. Immunohistochemical staining of the basaloid carcinoma revealed cytokeratin 34betaE12 immunoreactivity without expression of prostatic specific antigen and prostatic acid phosphatase. CONCLUSION: This case is a very unusual basaloid carcinoma and may indicate that there is a spectrum in prostate basal cell proliferation.