Cystic Nephroma of the Kidney

Adam J. Singer, MD, Southern California Permanente Medical Group, Woodland Hills

Disclosures

Infect Urol. 2001;14(1) 

In This Article

Introduction

A 30-year-old man who had recently moved to the United States from Hungary was referred to our urology service because of dull, aching pain in the left flank of 3 months' duration. He denied voiding problems, trauma, and previous urinary tract infections. He had been taking oral bopindolol, a nonselective b-blocker available in Hungary, for 2 years (1 mg each morning) for hypertension.

The patient's vital signs and physical examination were unremarkable. The complete blood cell count, serum electrolyte levels, blood urea nitrogen level, liver function tests, urinalysis, chest radiograph, and bone scan were normal. His serum creatinine level was 1.2 mg/dL (normal, 0.7 to 1.3 mg/dL).

Renal ultrasonography demonstrated a normal right kidney; however, there were multiple cysts replacing the majority of the left kidney, which also contained 4 stones. CT scans of the abdomen also revealed the cysts (Figure 1). In addition, there were 4 stones (3 measuring 4 to 5 mm in diameter and 1 measuring 1 cm in diameter) in the middle pole of the left kidney. There were no other abnormalities, and there was no evidence of metastasis. Results of cystourethroscopy and left retrograde ureteropyelography were normal and showed that all 4 stones were within the minor calices of the kidney.

. (A) CT scan, following the administration of oral contrast and before intravenous contrast, reveals multiple cysts replacing the majority of the left kidney, 3 renal stones (the fourth stone is not demonstrated), and no evidence of metastasis. (B) CT scan, following the administration of oral and intravenous contrast, shows extensive cystic replacement of the left kidney and a rim of functioning renal parenchyma anterolaterally. The renal stones are not shown.

. (A) CT scan, following the administration of oral contrast and before intravenous contrast, reveals multiple cysts replacing the majority of the left kidney, 3 renal stones (the fourth stone is not demonstrated), and no evidence of metastasis. (B) CT scan, following the administration of oral and intravenous contrast, shows extensive cystic replacement of the left kidney and a rim of functioning renal parenchyma anterolaterally. The renal stones are not shown.

An adrenal-sparing left radical nephrectomy was performed. Pathologic examination of the resected specimen demonstrated cystic nephroma (Figure 2).

. On gross sectioning, the bivalved left kidney demonstrates a conglomeration of noncommunicating cysts circumscribed by a thick pseudocapsule. The lesion is 17 X 12 X 8 cm. The intervening septa do not contain nodular masses but have rare foci of dystrophic calcification and renal tubules.

Which of the following is a correct statement about cystic nephromas of the kidney?

  1. Cystic nephromas are malignant.

  2. Cystic nephromas rarely occur in patients before age 2 years.

  3. A combination of radiographic imaging studies and percutaneous biopsies can unequivocally exclude an associated malignancy when cystic nephroma is suspected before surgery.

  4. The treatment of choice for cystic nephroma is surgical extirpation.

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