成人にみられた網膜芽細胞腫の1例

Unilateral retinoblastoma in an 18-year subject

　網膜芽細胞腫の成人例は稀であり，手拳大ほどの著明な眼球の伸展拡大と眼球突出を来たした報告例は，文献的に調べえた限りでは，わずか2例のみであった．自験例は視力低下と視野障害を訴え，左眼内腫瘍の診断を受けたが，約2年半来院せず放置していたところ眼球打撲を契機とし，腫瘍の急速な発育によって眼球の伸展拡大と著明な眼球突出を来たした21歳男子の症例である．CT検査では，著明に拡大した左眼球は眼窩をほぼ充満し，上顎洞内への浸潤が認められた．全身的には転移病変はなく，放射線治療の後に，上顎洞部分切除を含む眼窩内容除去術を行った．病理組織学的には未分化型綱膜芽細胞腫であった．現在術後9カ月を経過するが，再発および転移の微候は認められていない．

A 18-year-old male developed loss of vision in the left eye 3 months ago. The vitreous cavity was filled by proliferated masses with the visual acuity reduced to light perception. Two small high-density areas were detected by CT scanning. The diagnosis of intraocular tumor was made but the patient failed to be seen by us until 27 months later.

The left eyeball had now markedly enlarged and protruded, measuring 42 × 40 × 25mm in dimensions. The left eye and the left maxillary sinus was invaded by the tumor mass. Orbital exenteration and partial resection of the maxillary sinus was performed after a presurgical irradiation totalling 4, 650 rad.

The surgical specimen showed the anterior ocular segment to be markedly destroyed by the tumormass. The ocular cavity was filled by dark brownish solid mass. Microscopically, this tumor mass was composed of nests of small-sized round cells with hyperchromatic nuclei and scanty cytoplasm. These nests were scattered among spongy fibro-glial sup-portive tissue affected with necrosis, degeneration, hemorrhage and calcified foci. These findings were consistent with undifferentiated retinoblastoma. Tumor cells were seen in the degenerated fibrous tissue and were absent in the sclera. Nine months after surgery and at the age of 22, the patient is doing well without recurrence or metastasis.