A 60-year-old immigrant from India comes to the physician because of intermittent fevers and weight loss over the last 3 months. For the past 10 days, he has also experienced a dull ache in the right side of his abdomen. He considered himself healthy until 3 months ago. He denies anorexia, vomiting, diarrhea, jaundice, or dysuria. His past medical history is unremarkable.
His temperature is 37.9 C (100.2 F) , blood pressure is 128/82 mm Hg, and pulse is 84/min. His BMI is 22 kg/m². Pulse oximetry shows oxygen saturation of 97% on room air. His mucous membranes are moist. Cardiopulmonary examination is normal. There is no hepatosplenomegaly, but there is some pain to deep palpation in the right flank.
Laboratory results are as follows:

Which of the following is the most likely diagnosis?

Question

A 60-year-old immigrant from India comes to the physician because of intermittent fevers and weight loss over the last 3 months. For the past 10 days, he has also experienced a dull ache in the right side of his abdomen. He considered himself healthy until 3 months ago. He denies anorexia, vomiting, diarrhea, jaundice, or dysuria. His past medical history is unremarkable.
His temperature is 37.9 C (100.2 F) , blood pressure is 128/82 mm Hg, and pulse is 84/min. His BMI is 22 kg/m². Pulse oximetry shows oxygen saturation of 97% on room air. His mucous membranes are moist. Cardiopulmonary examination is normal. There is no hepatosplenomegaly, but there is some pain to deep palpation in the right flank.
Laboratory results are as follows:

Which of the following is the most likely diagnosis?

Quizplus · Accepted Answer

11ec193a_9825_bbea_853d_e3d060fdf596_MD0002_00 This patient's constitutional symptoms, microscopic hematuria, and significant erythrocytosis (without tri-linear bone marrow hyperplasia) are consistent with likely renal cell cancer. In the United States, > 80% of renal cell cancers are found incidentally when abdominal imaging is performed for another reason. These incidentally discovered renal cell cancers are almost always small and asymptomatic, and offer a good chance for removal and cure. More advanced renal cell cancers can have several associated paraneoplastic symptoms/conditions as shown in the table. Commonly associated conditions include non-metastatic liver function abnormalities (e.g., elevated alkaline phosphatase), unexplained fever and weight loss, hypercalcemia, and erythrocytosis (due to tumor cell production of erythropoietin). However, it is important to note that anemia is more common than erythrocytosis in these patients. Diagnosis is usually suggested by abdominal imaging (e.g., CT or ultrasound), but imaging cannot adequately distinguish benign from malignant tissue. As a result, nephrectomy is usually required for confirmation. (Choice A) Nephrolithiasis typically presents with flank pain that radiates to the groin, gross or microscopic hematuria, and possible dysuria as the stone passes. This patient's pain history (10 days, no dysuria) and lack of significant hematuria or flank pain make this diagnosis less likely. (Choice B) A perinephric abscess usually presents with fever, flank pain, and leukocytosis. However, this patient's erythrocytosis and normal WBC make this option less likely. (Choice D) Schistosoma japonicum is the most common form of schistosomiasis in Southeast Asia, but it usually does not involve the genitourinary tract. Schistosoma mansoni and haematobium can involve the genitourinary tract, but are commonly found in Africa (hematobium and mansoni) or South America (mansoni). In addition, schistosomiasis is not usually associated with erythrocytosis. (Choice E) Renal tuberculosis usually presents with sterile pyuria and gross hematuria. Although tuberculosis is common in Asia, it is usually not associated with the erythrocytosis seen in this patient. Educational objective: Renal cell cancer can be asymptomatic or present with abdominal pain, abdominal mass, and hematuria. Advanced renal cell cancer can be associated with a variety of paraneoplastic symptoms including hypercalcemia, erythrocytosis, and weight loss. __________ References: Tumor cells are the site of erythropoietin synthesis in human renal cell cancer associated with erythrocytosis. (http://www.ncbi.nlm.nih.gov/pubmed/2297568) Renal cell carcinoma. (http://www.ncbi.nlm.nih.gov/pubmed/19269025)

A 60-Year-Old Immigrant from India Comes to the Physician Because