Intrathoracic fat. A new CT feature of intrathoracic rib. Case report.

A case of intrathoracic rib in a 55-year-old woman is described. A plain chest film showed a rib forking and a pleural based opacity. Computed tomography (CT) showed the lower arm of the rib fork to be "intrathoracic" and the pleural based opacity to be due to pleural tent and intrathoracic fat. Twenty cases have so far been reported, only few were studied by CT scan. The presence of intrathoracic fat has not previously been described in these cases. The types of intrathoracic rib including pseudo intrathoracic rib of newborn infants are discussed.