上眼瞼のメルケル細胞癌の1例

A case of Merkel cell carcinoma in the upper eyelid

　81歳女性の上眼瞼メルケル細胞癌を経験した。腫瘍は充実性で表面は平滑，暗赤色調で血管拡張を伴っていた。瞼板を含めた眼瞼広範囲切除と硬口蓋粘膜を用いた再建術を行い，術後は耳下腺部リンパ節に50Gyの予防的放射線照射を行った。摘出した腫瘍の組織検査では小型で円形な腫瘍細胞が，真皮から皮下脂肪組織にかけて不規則な胞巣状に増生し，リンパ管内にも腫瘍細胞の浸潤があった。腫瘍細胞の核細胞質比は大きく，核は繊細なクロマチンを有し，核分裂像があった。特殊染色ではGrimelius染色で陽性，免疫組織化学染色ではkeratin, neuron specific enolase, chromogranin, S−100蛋白で陽性所見であった。

A 81-year-old woman was diagnosed as Merkel cell carcinoma in the right upper eyelid. The skin overlying the tumor was smooth and reddish-purple with telangiectasia. After total excision, lid plasty was performed using mucous memebrane from the hard palate. The parotid lymph node was irradiated totalling 50Gy. Light microscopy showed small round cells, arranged irregularly in sheets, invading the dermis, subcutaneous tissue and the lymph duct. Tumor cells showed scant cytoplasm and large nuclei containing fine chromatin. Some cells showed karyomiotosis. They stained positive on Grimelius staining and immunohistological staining for keratin, neuron specific enolase, chromogranin and S-100 protein. These features indicated neural and epidermal differentiation of tumor cells.