Each week, Osmosis shares a USMLE® Step 1-style practice question to test your knowledge of medical topics. Today’s case involves a 60-year-old man with pain in his scrotum. The scrotum appears to be swollen and the man’s vision has become blurrier. Can you figure it out?
A 60-year-old male comes to the physician’s office due to scrotal pain for the past 2 weeks. The patient describes a dull pain and noticed that his scrotum appears larger. He also felt fatigued and hot for the past 2 months and thinks that his vision has become blurrier. Medical history is significant for hypertension and hyperlipidemia. The patient has smoked one pack of cigarettes per day for 30 years. Medications include lovastatin and ramipril. The patient’s temperature is 37.7 °C (99.9 °F), pulse is 80/min, and blood pressure is 145/85 mmHg. Physical examination reveals facial flushing. Examination of the scrotum shows left-side swelling, which is not reduced when the patient is lying down. When light is applied to the testicle, it does not transilluminate. This patient’s underlying condition most likely originated from which of the following areas?
A. Bone marrow
B. Testicles
C. Kidney
D. Lung
E. Bone
Scroll down to find the answer!
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The correct answer to today’s USMLE® Step 1 Question is…
C. Kidney
Before we get to the Main Explanation, let’s look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!
Incorrect Answer Explanations
The incorrect answers to today’s USMLE® Step 1 Question are…
A. Bone Marrow
Incorrect: Polycythemia vera is a myeloproliferative disorder in which the bone marrow makes too many red blood cells. Occasionally, the condition may result in the overproduction of white blood cells and platelets as well. Although this patient’s hypertension, blurry vision, and facial flushing can also be seen in polycythemia vera, varicoceles are not expected.
B. Testicles
Incorrect: Testicular tumors also do not transilluminate, but these tumors usually present with a testicular mass rather than swelling. Also, a testicular tumor would not explain the patient’s hypertension, facial flushing, and blurry vision.
D. Lung
Incorrect: Lung tumors are not associated with polycythemia as a paraneoplastic syndrome, and therefore, they will not cause facial flushing or blurry vision. Also, a lung tumor would not explain the patient’s testicular findings.
E. Bone
Incorrect: Bone tumors are not associated with polycythemia as a paraneoplastic syndrome, and therefore, they will not cause facial flushing or blurry vision. Also, a bone tumor would not explain the patient’s testicular findings.
Main Explanation
This patient has a significant smoking history and hypertension, and he is now presenting with fatigue, low–grade fever, and blurry vision. This presentation, along with the physical exam showing testicular swelling that is not reduced when lying, is suggestive of a renal tumor. Varicoceles that fail to empty when the patient is recumbent are highly suspicious for a kidney tumor that obstructs the gonadal vein where it enters the renal vein. The facial flushing, hypertension, and blurry vision are most likely secondary to ectopic production of erythropoietin by the renal tumor.
Renal cell carcinomas (RCCs) are the most common primary tumors of the kidney, originating from the proximal convoluted tubules within the renal cortex. Transitional cell carcinomas of the renal pelvis are the second most common. Patients with RCC can present with a variety of symptoms, but unfortunately, such symptoms usually occur late in the course when metastasis has already occurred. The classic triad of RCC includes flank pain, hematuria, and palpable abdominal renal mass. Hematuria occurs when the tumor invades the collecting system. When the tumor invades the inferior vena cava, it may lead to lower extremity edema, ascites, hepatic dysfunction (related to Budd-Chiari syndrome), and pulmonary emboli. RCC can cause various paraneoplastic syndromes including polycythemia/ erythrocytosis (due to EPO production), hypercalcemia (due to PTHrP production). Increased incidence of RCC is associated with smoking and obesity.
Major Takeaway
Renal cell carcinoma is the most common primary tumor of the kidney. The classic presentation includes flank pain, hematuria, and palpable abdominal renal mass, but may occur late in the course. The presence of varicocele that is not reduced when the patient is recumbent is highly suspicious of malignancy of the kidney.
References
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The United States Medical Licensing Examination (USMLE®) is a joint program of the Federation of State Medical Boards (FSMB®) and National Board of Medical Examiners (NBME®). Osmosis is not affiliated with NBME nor FSMB.
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