眼瞼外毛根鞘腫の2例

Two cases of trichilemmoma in the eyelid

要約　目的：眼瞼に外毛根鞘腫を認めた2例の報告。

症例：症例1は78歳，女性。2年前から存在する眼瞼腫瘍切除目的に初診した。左上眼瞼外側皮膚に3.5mm×4.0mmの黄白色調，中央部には陥凹を伴い，同部位に角質様の付着物を伴う腫瘤を認めた。全摘出したところ，切除組織は，HE染色で胞巣の一部に淡明な腫瘍細胞が柵状配列を呈しており，外方増殖と内方増殖を同時に示していた。表層には錯角化を認め，腫瘍細胞の一部に核周囲のhaloを伴っており，外毛根鞘腫と確定診断した。切除後3か月において，明らかな腫瘍の再発はない。症例2は74歳，女性。1年半前，右上眼瞼内側に腫瘤を自覚し，初診した。初診時，右上眼瞼内側皮膚に大きさ7mm×5mm，色調は黄色，中央部には陥凹し，付着物と軽度の睫毛禿を認める腫瘍を認めた。腫瘤を生検し，切除組織はHE染色で症例1と同様の所見を認め，外毛根鞘腫と確定診断した。残存腫瘍を余剰皮膚とともに切除し，切除後半年において再発はない。

結論：外毛根鞘腫は眼瞼にも生じうるため，鑑別診断の1つに挙げておく必要がある。

Abstract　Purpose：To report two cases of eyelid trichilemmoma.

Case：Case 1 is a 78-year-old woman. She had had left upper eyelid tumor for 2 years. At the first admission, the mass was located on the outside of her left upper eyelid, messuring 3.5 mm×4.0 mm with a depression in the center, had hyperkeratotic deposits. The color of the mass was yellow-white. After the tumor was removed, pathological examination revealed that the tumor was composed of pale-staining cells in some parts of the alveolar nest by HE staining, and palisading at the periphery of the lesion. Outward growth and inward growth were shown simultaneously. Parakeratosis was observed on the surface, and some of the tumor cells were accompanied by a perinuclear halo which showed that the tumor was a trichilemmoma. There has been no recurrence of the tumor for 3 months after resection. Case 2 is a 74-year-old woman. She had suffered from a right upper eyelid tumor for 1 year. The mass measured 7 mm×5 mm with a depression in the center, had deposits and there was mild eyelash baldness. The color of the tumor was yellowish. The mass was removed and showed histopathological features similar to Case 1, revealing typical patterns of trichilemmoma.

Conclusion：We experienced cases of trichilemmoma located in the eyelash region. We should consider trichilemmoma in the differential diagnoses of masses located on the eyelid.