Step 1: Pott's puffy tumor, first described by Sir Percivall Pott in 1760, is a subperiosteal abscess of the frontal bone associated with underlying osteomyelitis.
Step 2: It usually complicates frontal sinusitis (or trauma), with infection spreading either directly or haematogenously to the frontal bone, producing a doughy, tender swelling over the forehead, which gives the lesion its name.
Step 3: Inward spread can cause serious intracranial complications such as epidural abscess, subdural empyema, brain abscess, and cortical vein thrombosis.
Step 4: The lesion involves the frontal bone, not the ethmoid, and it is an abscess with osteomyelitis, not a mucocele. Hence option (a) is correct.