光干渉断層計で網膜内顆粒層に囊胞様変化を示した下垂体腺腫の1例

A case of pituitary adenoma associated with microcystic change in the inner nuclear layer detected by optical coherence tomography

要約　目的：下垂体腺腫による視交叉圧迫・視野異常をきたし，光干渉断層計（OCT）で網膜内顆粒層（INL）の囊胞様変化がみられた1症例を報告する。

症例：47歳，男性。1年半前から徐々に進行する右眼の視力低下と視野の狭窄を主訴に近医を受診し，精査目的に当科に紹介となった。

所見：矯正視力は右0.2，左1.2，眼圧は右21mmHg，左21mmHg。相対的瞳孔求心路障害なし。前眼部・中間透光体に異常所見はなく，検眼鏡所見も異常はなかった。OCTの黄斑部B-scanで右眼傍中心窩のINLに囊胞様変化があり，en face画像では両眼で同部位に蜂の巣状の変化を呈した。網膜電図，多局所網膜電図で明らかな異常はなかった。ゴールドマン視野計検査で両耳側半盲を呈し，OCTのretinal ganglion cell-inner plexiform layer厚解析において視野変化に一致した両眼鼻側の菲薄化が確認できた。頭部MRIで視交叉を圧迫する下垂体腺腫があり，当院脳神経外科へ紹介し下垂体腫瘍摘出術を施行された。術後は視野障害の改善がみられたが，INLの囊胞様変化は両眼で拡大していた。

結語：INLの囊胞様変化は網膜疾患だけでなく，視神経疾患でみられることがある。En face画像を含めたOCTが検出に有用である。

Abstract　Purpose：To report a case of pituitary adenoma, which caused optic chiasm compression and visual field abnormality associated with microcystic change in the inner nuclear layer（INL）as detected by optical coherence tomography（OCT）.

Case：A 47-year-old man was referred to us for the gradual decrease of visual acuity and narrowing of his visual field starting one and a half years ago.

Finding and Clinical Course：Best corrected visual acuity was 0.2 in the right eye and 1.2 in the left. Intraocular pressure was 21 mmHg in both eyes. Relative afferent pupillary defects were not observed. Examination using a slit lamp did not show any abnormality in the anterior segment, intermediate translucent body and fundus. B-scan of OCT showed microcystic change in the INL of the macula of the right eye. An en face image of OCT showed a honeycomb-like change in the macula of both eyes. Electroretinogram（ERG）and multifocal ERG（VERIS）did not show obvious abnormalities. A Goldmann perimeter examination showed bitemporal hemianopia, and analysis of retinal ganglion cell-inner plexiform layer thickness using OCT confirmed thinning of the nasal side of both eyes consistent with visual field changes. Pituitary adenoma that compressed the optic chiasm was detected by magnetic resonance imaging（MRI）. The patient was referred to the department of neurosurgery and pituitary tumor resection was performed. After surgery, though an improvement in visual field was observed, the microcystic change in INL deteriorated in both eyes.

Conclusion：Microcystic change in INL is seen not only in retinal disease but also in optic nerve disease. Using OCT image including en face image is helpful in detecting microcystic change.