Sphenoid mucocele - an unusual mimic of pituitary adenoma
Meegan, J., Jeyaraman, K., Mendoza, N., Mehta, A., Zac-Varghese, S
Imperial College Healthcare NHS Trust
A 27-year-old gentleman with a 2-year history of uninvestigated sinus problems presented to his local district general hospital with a 2 week history of severe frontal headaches worse on straining and associated with intermittent vomiting. He had acute deterioration in his vision, diplopia and right-sided facial numbness.
On examination he had a left CN VI palsy and reduced sensation in the maxillary distribution of CN V.
CT head showed a large mass (4.7 x 4.3 x 3.7cm) centered on the pituitary gland associated with significant bony erosion and extension into the nasal cavity and nasopharynx. He was urgently referred to the pituitary services at Charing Cross Hospital for further investigation.
Formal assessment of visual fields was normal. An MRI with contrast revealed the mass to have thin and well-defined bony margins, associated with slow remodelling and expansion. T2 hypointense components were also identified inferiorly. This appearance is most compatible with a sphenoid sinus mucocele.
A pituitary profile was grossly normal with mildly elevated prolactin (334 milliunit/L) and normal cortisol and thyroid function tests.
The patient was referred to the ENT surgeons for management of the mucocele and is due to have an elective drainage and biopsy.
Mucoceles are collections of mucoid secretions and epithelium and can be thought of as cyst like lesions. Mucoceles arising from the sphenoid sinus are extremely rare (1-2% of all mucoceles). Pure cystic lesions within the sella turcica may appear clinically and radiologically as pituitary adenoma. The lesions occupy space and may cause disturbance of pituitary function; these can be associated with significant complications due to the compression of structures adjacent to the sinus. Most non-neoplastic sellar cysts can be approached through the trans-sphenoidal route, but large lesions with suprasellar extension may require transcranial surgery.