Review Question - QID 213764

A 44-year-old man presents to the emergency department with dark urine. He says it started last night and has persisted to this morning. The patient states he is generally healthy and has not seen a doctor in 2 years. He has a 5 pack-year smoking history and drinks alcohol on the weekends. He has had a few colds over the past several months, but no major medical issues. The patient states he has lost 7 pounds over the past 2 months as well. He also states he has pain over the his back that is episodic and severe and occurs when lifting objects. His temperature is 98.5°F (36.9°C), blood pressure is 139/80 mmHg, pulse is 96/min, respirations are 15/min, and oxygen saturation is 98% on room air. A urine dipstick is ordered as seen below.

Urine:
Color: Amber
WBCs: Positive
Protein: Positive
Glucose: Negative
Ketones: Negative
Blood: Positive

Which of the following is the most likely etiology of this patient's symptoms?