不完全切除で再発を来した成人女性の仙骨前部類表皮嚢腫の1例 A Case of a Recurrent Presacral Epidermoid Cyst in an Adult Woman

症例は46歳，女性．検診の腹部超音波検査で下腹部に約6cmの腫瘤を指摘され当院を紹介された．直腸指診で直腸後壁に弾性軟，表面平滑な腫瘤を触知した．骨盤CT，MRI検査で仙骨前面に内部がほぼ均一で境界明瞭な約6cmの嚢胞性腫瘤を認めた．40歳時に骨盤内の類表皮嚢腫で手術歴があることからその再発を疑い経腹的腫瘤摘出術を施行した．腫瘤は表面平滑，弾性軟，単房性嚢胞で内容物は灰白色の粥状物だった．病理組織学的には，嚢胞壁には角化をともなう重層扁平上皮がみられ炎症のため広範囲に上皮欠損をともなっていた．皮膚附属器はみられず類表皮嚢腫と診断された．本症は，悪性化の報告がまれにあり外科的な完全摘出が望ましいと考えられる．

A 46-year-old woman was admitted for treatment of a lower abdominal mass 6cm in size, which was detected by ultrasonography. Digital examination indicated an elastic soft and smooth surface tumor. Computed tomography and magnetic resonance imaging showed a cystic tumor 6cm in size, which was homogeneous and had a clear boundary. We conducted laparotomic mastectomy for the tumor. The tumor had a smooth surface, was elastically soft, and monocystic, and had dregs similar to those found in tofu in itself. Histopathologically, the tumors wall was keratinized squamous epithelium with no cutaneous adnexal structures. From these findings, we made a definitive diagnosis of an epidermoid cyst. Once diagnosed, however, surgical resection is mandatory because of the tumors malignant potential.