What is the differential? Which of these should be considered the diagnosis until excluded?
An ill-defined region of consolidation has a broad differential including various infections, tumours, haemorrhage and chronic scarring. In an immunocompromised patient, angioinvasive aspergillosis needs to be excluded.
As a first step, what is the easiest way of establishing whether or not this is an acute or chronic finding?
Check previous films if available.
In the left mid-zone a region of ill-defined opacity is noted (blue dotted line), seen anterior to the oblique fissure (red dotted line) on lateral projection, thus within the left upper lobe.