MR imaging of mucoceles of the sphenoid sinus.

Mucocele of the sphenoid sinus is a rare disorder [1-3]. Its clinical manifestations are varied, primarily reflecting the intimate anatomic relationships between the sphenoid sinus and cranial nerves 11-VI, the cavernous sinus, internal carotid arteries, pituitary gland, and optic chiasm [2, 4-8]. Two patients presenting with cranial nerve deficits were evaluated with CT and MR imaging. CT showed bone destruction and opacification of all or part of the sphenoid sinus, and revealed the presence of modest contrast enhancement. MR findings consisted of slightly increased signal intensity on T1weighted scans with marked but somewhat irregular increased signal intensity on the T2-weighted scans. Extension of the lesion outside the bounds of the sphenoid sinus into the clivus was evident in one case and led to consideration of clival chordoma as a strong differential diagnostic possibility. While CT findings of sphenoid sinus mucocele have been described [6-9] , to our knowledge this is the first report of the MR characteristics of this disorder.