Renal Carcinoid Tumor : A Case Report

A right renal tumor was incidentally found in a 38-year-old woman by annual medical check up. She visited our hospital for further examination and treatment. She did not show typical symptoms of carcinoid. A computed tomography (CT) revealed a calcified solid tumor in the upper portion of the right kidney. The tumor was 6.0 cm in diameter and was not enhanced in either early or late phase. There was no evidence of extrarenal invasion or distant metastasis. Based on a clinical diagnosis of stage 1 renal cell carcinoma, laparoscopic nephrectomy was performed. The pathological diagnosis was renal carcinoid tumor. The tumor had trabecular and ribbon-like structures with a thin fibrovascular stroma. Immunohistochemicaliy, the tumor cells stained positive for chromogranin A, synaptophisin and CD56. The cell proliferation rate was estimated to be under 1% with Ki67 staining. To find the primary lesion, we performed upper and lower gastric endoscopy and chest computed tomography, but could not find any/other carcinoid tumors. At 1-year follow up, she had no evidence of local recurrence or metastasis.