Incidentally detected renal adenomatosis in a patient with urolithiasis: a case report

Renal adenomatosis

Adenomatosis is a rare lesion of unknown etiology, defined as multiple (usually 5 or more) adenomas in one kidney. A case of renal adenomatosis in a 68-year-old woman treated previously for urolithiasis, who underwent nephrectomy because of the nonfunctional left kidney is reported. Apart from multiple adenomas, numerous hyperplastic lesions involving single tubules were present in the resected kidney. Both adenomas and hyperplastic lesions exhibited the expression of alpha-methylacyl-coenzyme A racemase (AMACR). Renal adenomatosis is worth special attention, since renal papillary adenomas are suggested as precursor lesions of papillary renal cell carcinoma that show similar AMACR expression.

Oncocytic Papillary Renal Cell Carcinoma in the Background of Renal Adenomatosis

Renal adenomatosis is a rare disease characterized by numerous adenomas in bilateral kidneys. A literature review shows that malignant tumors can arise in this condition. The present case describes an oncocytic papillary renal cell carcinoma (PRCC) arising in renal adenomatosis. A 70-year-old man presented with incidentally identified, multiple right renal masses on computed tomography. Right nephrectomy was performed, and the resected kidney revealed numerous radiologically undetected small nodules additionally. Microscopically, the nodules were papillary neoplasms of variable sizes and cytological features. The largest nodule measured 1.6 cm and was composed of oncocytic cells, meeting the diagnostic criteria of oncocytic PRCC. The smaller nodules of papillary adenomas and tiny lesions showing a single papillary ingrowth were also seen. This case exhibits a spectrum of renal papillary neoplasms in a resected kidney and can be a valuable case in the understanding of tumorigenesis.