A 35-year-old man presents with upper back pain for two weeks, which is constant and dull in nature, without radiation. Both weight-bearing and movement aggravate the pain. There is no weakness or numbness of the upper or lower limbs.
Further questioning reveals an intermittent nonproductive cough for one and a half years, associated with anorexia and fatigue, and a total weight loss of ~10 kg.
There is no history of trauma, exposure to tuberculosis, animal contact, or foreign travel within or immediately before that period. He has been healthy until now and is not on any medications.
His family history is only significant for a myocardial infarction in his father, at the age of 62 years. He has smoked for 15 years and continues to do so, consuming around two to three cigarettes per day. He only drinks socially and denies using recreational drugs.
A complete blood count is significant for a Hb of 9.5 g/dL (normal: 11-18), with a MCV of 85 fL (normal: 75-95). His ESR and CRP are 82 mm/1h (normal: <10) and 24 mg/L (normal: <6) respectively. Chest x-rays reveal a heterogeneous opacity in the left upper lobe.