プロラクチン産生下垂体腺腫の変性に続発した第三脳室のトルコ鞍内陥入によるEmpty Sella

Empty sella as an Intrasellar Herniation of the Third Ventricle Secondary to the Spontaneous Degeneration of the Pro-lactinoma

I．はじめに

　Secondary empty sellaは手術後または放射線療法後のものが多いが，下垂体卒中によるとの報告も見られる^3,24）．また，トルコ鞍内に陥入するのは，大多数でくも膜下腔であるが，時に第三脳室も陥入する^{1,18,19,21）}．われわれは，prolactinomaの鞍内変性壊死部に第三脳室が陥入してempty sellaを形成した症例を経験したので，その形態・発生機序・治療について検討した．

A case of a large empty sella was reported, which was intrasellar herniation of the third ventricle associ-ated with a prolactinoma. The patient was a 46-year-old female admitted due to consciousness disturbance with pyrexia and vomiting. She had amenorrhea, galactor-rhea and sterility in her past history. On admission, physical and neurological examinations revealed severe dehydration, systemic edema, systemic hypotension, nuchal rigidity, papilloedema and goiter. A spinal tap was performed and revealed an increase in CSF pres-sure. Laboratory data indicated CSF lymphocytosis, an increase in CSF protein content, high titers of serum microsome test, a low concentration of anterior pituit-ary hormones in serum except for PRL, and an un-usually high concentration of PRL in serum and CSF (4680 and 222ng/ml, respectively). Plain films of the skull showed destructive enlargement of the sella turci-ca. The patient was diagnosed as having non-bacterial meningitis, chronic thyroiditis and a prolactinoma with hypopituitarism and was then admitted to our depart-ment. Except for amenorrhea she was asymptomatic under the administration of levothyroxine, hydrocorti-sone and bromocriptin. CT scan, MRI, pneumoencepha-lography and CT cisternography as further examina-tions disclosed the intrasellar herniation of cisterns and the third ventricle, which were surrounded by an in-trasellar parenchymal layer. This layer was thought to be still viable prolactinoma tissue. We supposed the third ventricle entered the enlarged sellar cavity follow-ing the spontaneous degeneration of the large prolacti-noma. Although we could find some documented re-ports of similar cases, the complete herniation of the third ventricle secondary to degeneration of an adeno-ma might be rare. Conservative treatment by bromo-criptin was chosen, because we thought surgical treat-ment, even a transsphenoidal operation, would have no advantages over conservative methods. A determination of operative indication requires careful consideration in a case of such complicated structure as this patient.