肺癌の虹彩転移に対し前房水細胞診が有用であった1例

Cytological biopsy was useful in a case of iris tumor metastatic from lung cancer

要約　目的：肺の扁平上皮癌が虹彩毛様体に転移し，前房水の細胞診が診断に有用であった症例の報告。

症例：54歳男性が左眼の充血と霧視で紹介され受診した。10か月前に肋骨移転を伴う肺の扁平上皮癌（Stage Ⅳ）と診断され，放射線照射と化学療法が行われていた。

所見と経過：左眼の矯正視力は1.2，眼圧は38mmHgであった。左眼の虹彩上方に隆起性病変と下方隅角を占拠する腫瘤があった。肺癌の虹彩転移を疑い，化学療法を再開した。1か月後に隅角の腫瘤と前房水を採取した。腫瘤は判定不能であったが，房水の細胞診で原発巣と類似した細胞が認められ，肺癌の虹彩転移と診断した。その後，虹彩腫瘍は化学療法の結果として縮小し，初診から7か月後に全身状態が悪化し，不帰の転帰をとった。

結論：転移性虹彩腫瘍は，頻度は稀であるが，生命予後が不良なため，診断には低侵襲の検査が望まれる。本症例では前房水の細胞診が低侵襲で，診断に有用であった。

Abstract　Purpose：To report a case of iris tumor metastatic from lung cancer who was diagnosed by cytological biopsy of the aqueous humor.

Case：A 54-year-old male was referred to us for hyperemia and blurring in the left eye. He had been diagnosed with Stage Ⅳ squamous cell carcinoma of the lung with metastasis to the ribs 10 months before, followed by radiation and chemotherapy.

Findings and Clinical Course：Visual acuity in the left eye was 1.2, with intraocular pressure of 38 mmHg. The left eye showed a swelling in the superior sector of the iris. A tumor was present occupying the inferior sector of the chamber angle. The finding suggested metastasis from the lung tumor to the iris. Chemotherapy was initiated followed by biopsy of the iris and aqueous humor one month later. While no conclusive diagnosis could be made from the iris tumor, cells in the aqueous were similar to those of the lung cancer. The iris tumor was thus identified as metastasis of lung tumor and regressed due to chemotherapy. The patient died 7 months after his first visit.

Conclusion：Metastatic iris tumor is relatively rare but needs less invasive diagnostic procedure. Biopsy of the aqueous humor was virtually non-invasive and was useful in the diagnosis.