下垂体膿瘍の3症例

Three Cases of Pituitary Abscess

I．はじめに

　ラトケ嚢胞や下垂体腺種に合併する下垂体膿瘍，あるいは原発性下垂体膿瘍の報告が増加しているが，実際われわれが目にする機会は少ない．この度われわれは下垂体膿瘍を3例経験したが，そのうち1例は，MRI上下垂体出血様の所見を示し，経過観察中に髄膜炎症状を来し，下垂体膿瘍を発症したものである．

We report three cases of pituitary abscess. Three patients, all females, had suffered headache and com-plained of general fatigue. In each case magnetic resonance imaging (MRI) revealed a sellar mass withsuprasellar extension. T1-weighted images revealed an isointense or slightly hypointense lesion with thinring-enhancement following gadolinium injection. No inflammatory signs were found in two cases.

In one case, a gradual change in clinical symptoms and MRI findings was noted : the hypophysealhemorrhagic lesion detected on MRI changed into a cystic lesion with thin ring-enhancement.

Transsphenoidal surgery was performed in all three cases. In each case, however, no organism was cul-tured and no tumor component was found.

It is difficult to diagnose pituitary abscess prior to surgery if no inflammatory signs are present. Diagno-sis of this condition requires careful radiological evaluation. Findings of a suprasellar round cystic mass with thin ring-enhancement on MRI associated with thick-ened stalk, hyperprolactinemia, and diabetes insipidus may be suggestive of a pituitary abscess.