Posterior mediastinal branchial cleft cyst: an unusual site.

A two and a half year old Kenyan girl presented with recurrent chest infections and difficulty in swallowing. Her clinical and laboratory workup was suggestive of lower respiratory tract infection for which she received a course of antibiotics; however, she remains symptomatic after the management of her suspected diagnosis. Therefore, further radiological workup including a chest CT scan and barium study were performed. This showed a homogeneous mass surrounded by ascending and descending aorta in the posterior mediastinum that was compressing the middle esophagus. She had a posterolateral thoracotomy which revealed a cystic mass with smooth surfaces (5x5 cm) in the posterior mediastinum. Histopathology showed branchial cleft cyst predominately lined by stratified squamous epithelium, with lymphocytes predominance. A final diagnosis of posterior mediastinal branchial cleft cyst was made. She was discharged home and remained well at follow-up.