Persistent hematuria caused by renal cell carcinoma after aortic valve replacement and warfarin therapy

Abstract

Hematuria is a common finding in renal cell carcinoma, and persistent hematuria, even in those receiving anticoagulation, warrants workup. We present a case of a patient with persistent hematuria who was found to have a renal mass that was not evident on renal ultrasound and computed tomography of the abdomen and pelvis but was seen on magnetic resonance imaging.

Hematuria is a common finding in urinary tract disease and may be self-limiting or persistent. The etiology can include infection, stones, immunological injury, or the presence of a renal mass. Even in anticoagulated patients, hematuria should be investigated, as anticoagulation per se is rarely a cause of hematuria (1). We present a case of renal cell carcinoma (RCC) in a patient on anticoagulation who had persistent gross hematuria. A renal mass was identified on magnetic resonance imaging (MRI) but was missed on earlier renal ultrasound and computed tomography (CT) of the abdomen and pelvis.

CASE PRESENTATION

A 67-year-old man with a past medical history of diabetes mellitus, hypertension, and nephrolithiasis after lithotripsy presented to the emergency department with a complaint of chest pain and was admitted for acute coronary syndrome. Cardiac catheterization showed severe multivessel coronary artery disease and severe aortic stenosis. The patient subsequently underwent coronary artery bypass surgery and mechanical aortic valve replacement. He was anticoagulated with warfarin and bridged with heparin drip (target international normalized ratio of 2.5 to 3.5). The next day, the patient developed gross hematuria and flank pain. Urinalysis showed a red blood cell count of >5 cells/high-power field and a white blood cell count of 0 to 2 cells/high-power field, with no bacteria, red blood cell casts, or white blood cell casts. A renal ultrasound revealed mild right renal hydronephrosis.

CT scan of the abdomen and pelvis (Figure 1) showed nonobstructing stones in the lower pole of the right kidney with fullness of the right renal pelvis. Cystoscopic removal of the right kidney stone was done with placement of a temporary stent. There was no evidence of a bladder lesion. Mild hematuria present after the procedure was considered iatrogenic. However, hematuria persisted with worsening of right flank pain, which warranted further workup. MRI of the abdomen and pelvis showed a 2.9 × 2.5 × 3.8 cm mass with enhancement within the right renal pelvis predominantly involving the lower portion, which was concerning for underlying malignancy or hematoma (Figure 2). The mass was not clearly visualized in imaging CT or ultrasound imaging. A urine cytology study showed no malignant cells. Tissue samples were obtained through ureterocystoscopy, and biopsy showed inflammatory cells (necrotic tissue), with no malignant cells. Because a concern for possible malignancy remained, an image-guided biopsy of the mass was attempted, although it was technically challenging due to the location and surrounding necrotic tissue at the site of the mass. The biopsy result was again negative for malignancy, showing only inflammatory cells.

Figure 1.

CT scan of the abdomen and pelvis showing a renal stone in the lower pole of the right kidney with mild hydronephrosis and fullness of the right renal pelvis.

Figure 2.

MRI of the abdomen and pelvis showing a renal mass (arrow) in the right kidney, as seen on (a) cross-section and (b) coronal section.

A multidisciplinary team recommended right nephrectomy as an option to both exclude malignancy and remove the source of hematuria. Right nephrectomy was performed successfully, with no complications. The renal tissue sent for biopsy showed a 7 cm mass extending into the renal pelvis. The tumor was T2N0M0, grade 2, clear cell RCC. The surgery was curative for the patient's tumor stage, and the patient was successfully anticoagulated, with no further hematuria during the hospital stay and following outpatient visits.

DISCUSSION

RCC is the most common type of kidney cancer in adults, responsible for approximately 90% to 95% of cases. Clear cell carcinoma is the most common type, representing about 70% of all RCC (2). Other neoplasms are transitional cell carcinoma of the renal pelvis, sarcoma, lymphoma, and Wilm's tumor. In an early stage, RCC presents mostly with nonspecific symptoms such as anorexia, tiredness, weight loss, or fever of unknown origin (3)—making early diagnosis difficult. The classic clinical triad of hematuria, flank pain, and a palpable flank mass occurs in only 5% to 10% of cases and often indicates a more advanced stage of the disease (4). Volpe et al proposed that the RCC incidence has increased mainly due to the widespread use of cross-sectional imaging; most renal tumors are detected incidentally as small, asymptomatic masses. This study indicated an incidental detection rate of approximately 48% to 66%, while that rate was only 7% to 13% in the 1970s (5). Most renal lesions are benign simple cysts, requiring no further workup. However, any solid renal mass or mixed solid and cystic mass should be considered malignant until proven otherwise and warrants further evaluation (6).

The standard evaluation of patients with suspected RCC includes urinalysis with cytology, chest x-ray, and CT scan of the abdomen and pelvis. RCC is generally a vascular tumor, and angiography was a common investigation to assess vascularity preoperatively. However, angiography is not routinely used anymore due to the availability of less-invasive options such as spiral CT scan or dynamic magnetic resonance angiography. The combination of renal ultrasound and CT scan is more sensitive for the diagnosis and gives sufficient information for surgical intervention (7, 8). Furthermore, the diagnostic and staging value of angiography is limited compared to CT scan. Angiography still retains its usefulness in exceptional situations where interventional arteriography needs to be done, such as for acute hemorrhage or embolization of potentially bleeding tumors (8). MRI as a diagnostic tool is sometimes required when indeterminate lesions are located or when a hyperattenuating renal mass is seen on CT scan (9, 10), as was the case in our patient. This case should raise the level of awareness of the possibility of false-negative results of renal ultrasound or CT scan that warrants an MRI.

For the diagnosis of RCC, an image-guided renal mass biopsy is safe, reliable, and accurate. It changes clinical management in many cases by avoiding nephrectomy or other surgical options (11). Insufficient tissue size and sampling error along with smaller masses and masses with internal necrosis have been implicated in false-negative biopsy results (12). In our patient, it was concluded that due to the central necrosis and location of the mass, it was technically difficult to take adequate biopsy samples, which resulted in the false-negative biopsy results that necessitated a nephrectomy due to the high suspicion of malignancy.

Anticoagulation on currently recommended therapeutic levels rarely causes hematuria, and further workup, including MRI, appears warranted for persistent hematuria, even if renal ultrasound and CT scan are both negative for a renal mass.