Two resected cases of Mullerian cyst in the posterior mediastinum

Abstract

We report two resected cases of Mullerian cyst in the posterior mediastinum. Case 1: A 50-year-old woman was referred to us with a posterior mediastinal cystic tumor found during a systemic examination of a renal nodule. Magnetic resonance imaging revealed a 30 × 20-mm smooth-surfaced cyst with high-intensity signals in T2-weighted images on the left side of the Th7 vertebra. We diagnosed it as a neurogenic tumor and resected it by thoracosopic surgery. Histopathological examination revealed that the cyst had a thin fibrous wall covered with a single layer of cilliated columnar epithelium. Immunohistochemical staining was positive for estrogen and progesterone receptors in the epithelia. Finally, we diagnosed it as a Mullerian cyst. Case 2: A 36-year-old woman was referred to us with a nodule on the left side of the vertebra and cranial side of the aortic arch found on a chest radiograph during a medical check-up. Chest computed tomography revealed a 30 × 18-mm homogenous cystic lesion on the left side of the Th4 vetebra. We diagnosed it as a neurogenic tumor and resected it by thoracoscopic surgery. Histopathological examination revealed that the inner side of the cyst wall was lined with pseudostratified cilliated epithelium and we diagnosed it as a bronchogenic cyst. After encountering case 1, we additionally performed immunohistochemical staining. It was positive for estrogen and progesterone receptors in the epithelia. We corrected the diagnosis to a Mullerian cyst.