妊娠後期にmass effectで発症したリンパ球性下垂体前葉炎の1例

A Case of Lymphocytic Adenohypophysitis Presenting Visual Disturbance in the Third Trimester of Pregnancy

Ⅰ．はじめに

　リンパ球性下垂体炎は1962年にGoudieらによって初めて報告された疾患で⁴⁾，自己免疫による発症機序が考えられている．初期からadrenocorticotropic hormone（ACTH）分泌不全症状を呈するのが典型的であるが^5,6)，今回，妊娠中に視力視野障害で発症したリンパ球性下垂体前葉炎の1例を経験したので，文献的考察を加えて報告する．

　Lymphocytic hypophysitis（LH）has first been described as an autoimmune endocrinopathy by Goudie in 1962. In particular, lymphocytic adenohypophysitis（LAH）is usually associated with pregnancy and hypopituitarism due to insufficient endocrine of ACTH. However, several cases of LAH in pregnant patients showing only visual disturbances have recently been documented.

　We treated a patient with LAH presenting only the chiasma syndrome in the third trimester without hypopituitarism. A 27-year-old woman unexpectedly experienced visual disturbance starting in the 28th week of pregnancy. Her symptoms progressed rapidly. MRI revealed a pituitary mass lesion compressing the optic chiasma. In addition, ophthalmological examination revealed bitemporal hemianopsia.

　The patient underwent endoscopic transsphenoidal surgery（eTSS）during the 30th week of pregnancy. LH was diagnosed histologically during surgery. We performed decompression of optic chiasma. After surgery, the patient’s visual field markedly widened and the pituitary mass regressed along with replacement of corticosteroids. In the 37th week of pregnancy, she delivered a healthy baby.

　We speculate that the reason for the absence of hypopituitarism during pregnancy in patients with LH, especially in the third trimester, might be that the placental endocrine system masks pituitary endocrinopathy.

　In summary, we report a case of LAH that did not present with hypopituitarism, and eTSS could be performed safely during pregnancy.