Fetus in fetus (FIF) is an extremely rare congenital condition characterized by the parasitic development of a malformed fetal twin within a normal second twin's body. The localization is mostly abdominal in the retroperitoneum. Thoracic localization is extremely rare. In this clinical case, a 5 month old female infant weighing 5 kg presented with a chest mass causing respiratory distress. We realized a chest CT-Scan; the latter revealed a heterogeneous mass, completely occupying the left hemithorax. Imaging studies confirmed the presence of the fetus in fetus occupying the entire left hemithorax and mediastinum, pushing the heart to the right. A complete resection of the mass could be performed under general anesthesia and orotracheal intubation (GA + OTI). The monitoring involved ECG, SpO 2 , NIBP, PR, T°, and Capnometry. The ventilation was first mechanical and secondarily manual. The patient did not receive unipulmonary ventilation nor central IV line. Postoperative period marked by volume overload, anemia, cardiac arrest, with successful resuscitation. Histopathology studies and imaging confirmed the diagnosis. On D9, she was discharged from pediatric critical care and from hospital on day ten postoperative. She presented in good clinical condition after a 3-month follow-up. We report this case in order to show how we took care of this FIF case in the precarious conditions.

Sphenoid sinuses are carved into the body of the sphenoid bone. They are probably the most variably pneumatized structures of the skull. They begin their pneumatization at the age of three and finished at adolescence. Several anatomic variants of sphenoid sinuses have been described in the literature. The agenesis of sphenoid sinuses in adults is very rarely found. We report two incidental cases of sphenoid sinuses agenesis discovered on CT scan in Benin, West Africa.