A poor prognosis of a mediastinal bronchogenic cyst with malignant transformation: A case report

Bronchogenic cysts (BC) are congenital lesions, it results from an abnormal budding of the tracheobronchial tree. Malignant transformation is very rare. We report a case of adenocarcinoma arising in a BC of the posterior mediastinum detected after surgery.

We report the case of a 32-year-old man, without a particular medical history. The patient presented a cough associated with dyspnea, and a weight loss 4-month before the diagnosis. The imaging tools, showed a voluminous latero-tracheal mass of the posterior mediastinum. The diagnoses of a neurogenic tumor or a BC were suspected. The patient was treated by video-assisted thoracoscopy. Complete excision was done complicated by lesion's small rupture. The microscopic exam revealed unfortunately an adenocarcinoma arising in a BC. The patient had started the cure of chemotherapy. Six months later, the patient died due to tumor recurrence with cerebral metastasis.

Mediastinum BC, is usually located within the middle and posterior mediastinum. This condition is a benign congenital lesion. His curative therapy was a complete surgical resection with a good prognosis. However, malignant transformation may seldom occur and is most often accidentally diagnosed during the histological examination of specimens. In this case, the surgical treatment may be insufficient, and the prognosis may be poor.

Malignant degeneration of mediastinal BC, despite being rare, should be kept in mind, carefully avoided and managed.