Renal Mass (Case 18)

Published on 24/06/2015 by admin

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Chapter 25
Renal Mass (Case 18)

Azzour Hazzan MD

Case: A 46-year-old woman presents for an evaluation of hematuria and flank pain over the past few days. Her pain is dull without radiation, and she has no associated nausea or vomiting. She denies dysuria or frothy urine. Her father died at age 50 years from an intracranial aneurysm. Her exam is remarkable for elevated BP, distended flanks, and left flank tenderness to palpation.

Differential Diagnosis

Polycystic kidney disease (PCKD)

Renal cancer

Acquired cystic kidney disease

Renal manifestations of tuberous sclerosis and renal angiomyolipoma

Medullary sponge kidney (MSK) disease

 

Speaking Intelligently

Certain factors should be considered when evaluating a patient with a renal mass or renal masses. These include the ultrasonographic characteristics of the mass, the presence of patient-specific risk factors for renal malignancy, and systemic signs and symptoms that suggest specific diseases. For example, a 2-cm renal mass that is cystic in nature on ultrasound with no septations in a 30-year-old patient who is otherwise healthy is most likely a benign cyst and needs no further workup. Conversely, a 5-cm mass with complex features such as calcifications or septations in a 60-year-old patient with a history of anemia, fever, and weight loss is very suggestive of renal cell carcinoma.

PATIENT CARE

Clinical Thinking

• Renal lesions are most often discovered incidentally during abdominal imaging.

• Patients with PCKD usually have a family history of renal insufficiency and are hypertensive.

• Patients with acquired cystic kidney disease usually have a known history of renal disease, often requiring dialysis.

• Patients with MSK often give a history of nephrolithiasis and UTIs.

• Renal cancers are usually larger than 4 cm and often are associated with weight loss, fever, or hematuria.

• Hamartomas or angiomyolipomas can be part of a systemic syndrome such as tuberous sclerosis.

History

• Patients with PCKD often have a family history of PCKD with relatives requiring dialysis, as well as a family history of intracranial aneurysms. The patients often carry a diagnosis of hypertension and chronic kidney disease but may not have been diagnosed with PCKD. They can present with UTIs, kidney stones, or hematuria, but often they are asymptomatic and only diagnosed when multiple renal cysts are discovered on unrelated imaging.

• Patients with acquired cystic kidney disease usually have a known history of long-standing advanced chronic kidney disease. These cysts are more common in African-American men. They can present with painful hematuria but more commonly are asymptomatic and only discovered on unrelated imaging.

• The medullary cysts found as part of medullary sponge kidney disease can be diagnosed as part of the workup of the associated nephrolithiasis but are often found incidentally.

• Patients with renal neoplasm can present with fever and weight loss as well as hematuria and flank pain.

• Renal angiomyolipomas can be seen as part of tuberous sclerosis complex or von Hippel-Lindau (VHL) disease. When they are part of tuberous sclerosis complex, patients can have a history of seizures and mental retardation. When associated with VHL disease, they can be associated with retinal angiomas, and spinal and cerebellar hemangioblastomas.

Physical Examination

• Accurate BP measurement is essential. Although hypertension is not specific to any particular cystic entity, it is almost always seen in advanced PCKD and it is a target of treatment for all renal diseases.

• The abdominal exam ranges from unremarkable in cases of small cysts, to palpable masses with flank tenderness in cases of large cysts or renal masses.

• Hypomelanotic skin lesions, called ash-leaf spots, can be seen in tuberous sclerosis.

• Rarely, when a renal cancer invades and obstructs the left renal vein, this can result in a left testicular varicocele.

Tests for Consideration

• Basic metabolic panel to assess kidney function.
Serum creatinine can be abnormal in PCKD and acquired cystic disease. It is usually normal in medullary sponge kidney disease and renal cancer.

$12

• Renal biopsy: Biopsy samples of indeterminate lesions can help to determine a histologic diagnosis; biopsies are usually not done for cystic disease.

$676

• Genetic testing for polycystic kidney disease: Can be done if sonographic diagnosis is questionable or the patient is considering kidney donation.

$5275

 

IMAGING CONSIDERATIONS

→ Ultrasound is inexpensive and has an acceptable sensitivity for most diseases. It can readily distinguish solid from cystic lesions; however, it is operator dependent and is unable to distinguish vascular from nonvascular lesions. Ultrasound is a good initial test, because it can differentiate benign cysts from potentially malignant lesions. If the criteria for a simple cyst by ultrasonography are not satisfied, the patient should undergo CT scanning before and after injection of iodinated contrast.

$96

→ CT, with and without contrast, is helpful in evaluating cysts with complex components. CT urography allows imaging of both the renal parenchyma and the collecting system. Cysts or masses that enhance with contrast are concerning for malignancy.

$334

→ MRI

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