Picture of the Month Quiz

A previously well 16-year-old boy presented to his local hospital with intermittent pyrexia, diffuse headache, and a left-sided swelling that had gradually enlarged over the previous 7 days. Two weeks earlier, his general practitioner had diagnosed sinusitis and had prescribed a combination of amoxicillin and clavulanate, administered orally, which the patient only partially completed.

Results of a physical examination revealed a large tender, fluctuant lesion in the left parietal region of the skull. The remainder of the examination was unremarkable.

A computed tomographic scan of the head showed a large extracranial subgaleal abscess corresponding to the site of the swelling and showed osteomyelitis of the underlying skull. On admission, further evaluation with cranial magnetic resonance imaging showed mucosal swelling and opacities in his maxillary, ethmoid, and frontal sinuses bilaterally, indicating pansinusitis. An unexpected abnormality was also detected (Figure).



What is your diagnosis?

For a complete discussion of this month's case, read next month's Picture of the Month—Quiz Case.