Abstract
A Müllerian cyst arising in the posterior mediastinum was initially reported by Hattori in 2005. We report a 47-year-old woman with a Müllerian cyst in the posterior mediastinum, so-called Hattoriʼs cyst. A mediastinal mass was detected by chest X-ray. She exhibited no clinical symptoms associated with the mass. MRI revealed a cystic lesion between Th4/5. Preoperative diagnosis was a bronchogenic cyst. The lesion was resected thoracoscopically, and histologic and immunohistochemical stainings showed a cyst with ciliated epithelium that was positive for estrogen and progesterone receptors. The resected cyst was pathologically diagnosed as Müllerian cyst (Hattoriʼs cyst). Hattoriʼs cyst should be included in the differential diagnosis of posterior mediastinal cysts.
