剖検にて偶然発見された膀胱内に突出した尿膜管嚢胞の1例 ―病理学的検討及び最近10年間の文献的考察―

Abstract

79歳男.下部胆管癌により死亡した.剖検により, 発生部位が極めて稀な膀胱腔内に突出する尿膜管嚢胞を有することが明らかとなった.病理組織学的には, 嚢胞は正中膀胱壁の固有筋層内から生じ, ケラチン染色は強陽性であった.嚢胞壁は膠原線維より成り, 神経線維や筋組織を認めたが, 炎症細胞等の浸潤はなかった.この症例の非感染性尿膜管嚢胞は既知の五つのタイプとは全く異なる発生部位に由来するものであった.嚢胞壁と臍ならびに膀胱との交通は認められず, 尿膜管嚢胞の一亜型と考えられた

Disorders of urachal remnants are common. While urachal cysts are usually asymptomatic, infection may mimic a variety of acute abdomen. Here we report a very rare case of urachal cyst that protruded in the urinary bladder cavity and among 99 accumulated cases, only 4 cases have been reported similar to this case characterized by intravesical development from 1990 to 1999. An uninfected urachal cyst was found in a 79-year-old male who had died of bile duct carcinoma. The cyst showed ovoid protrusion into urinary bladder cavity from the dome (3.5 x 2.0 x 2.0 cm in size). Histopathologically, the cyst wall was thin and consisted of fibrous connective tissue with muscular tissue and peripheral nerve, and lined by cuboidal epithelium but no inflammatory cells could be seen. Urachal cysts occur in both sexes are affected with equal frequency, and frequently occur in a younger population. In clinical symptoms the umbilical manifestations are predominant in patients younger than 30 years old, while the bladder manifestations are predominant in those older than 30.