右下腹部に生じた嚢胞内出血を伴う中皮嚢胞の1例

A case of mesothelial cyst occurring in the right lower abdomen with intracystic hemorrhage

中皮嚢胞（mesothelial cyst）はまれな先天性嚢胞で，全身の様々な部位に発生する。多くは無症状だが，腹部や骨盤部に発生しサイズが大きいものは，周囲組織を圧排し腹痛や腹部膨満感などの症状を生じる。今回我々は，嚢胞内出血を伴った中皮嚢胞の1例を経験したので報告する。

The case is a 76-year-old woman. She noticed a palpable mass in her lower right abdomen and visited a previous doctor. She was found to be positive for urine occult blood in a urinalysis and was referred to the urology department of our hospital for a detailed examination. She had a cystic lesion with a bleeding component on the right side of her pelvis on CT and MRI. Postoperatively, she was diagnosed with a mesothelial cyst in histopathological diagnosis. For cystic masses that develop in the lower abdomen or pelvis, when the origin of the gastrointestinal tract or adnexal is unclear, it may be a good idea to include mesothelial cysts as a differential diagnosis.