Differential Diagnosis of mass-like density in lower hemithorax Intern 張敬弘

Mass-like density in lower hemithorax Subpulmonic pleural effusion Lobar atelectasis Paralysis of hemidiaphragm Eventration of diaphragm Tumor of diaphragm Subphrenic mass effect Pericardial cyst or fat pad Posterior mediastinal mass Hernias

Mass-like density in lower hemithorax Pericardial cyst or fat pad Posterior mediastinal mass Subpulmonic pleural effusion Lobar atelectasis Paralysis of hemidiaphragm Eventration of diaphragm Tumor of diaphragm Subphrenic mass effect Hernias

Pericardial cyst or fat pad No air Generally right-sided Fluid or fat density with cross-sectional imaging

Posterior mediastinal mass Neurofibroma, Schwannoma Usually paraspinal, Bochdalek hernias usually more lateral in location Germ cell tumor

Mass-like density in lower hemithorax Pericardial cyst or fat pad Posterior mediastinal mass Subpulmonic pleural effusion Lobar atelectasis Paralysis of hemidiaphragm Eventration of diaphragm Tumor of diaphragm Subphrenic mass effect Hernias

Subpulmonic pleural effusion The “dome” of pseudodiaphragm migrates toward the costophrenic angle and flattens Fluid may extend into fissures Decubitus chest radiographs can usually distinguish pleural fluid from true elevation

Lobar atelectasis Hilar displacement Mediastinal shift

Mass-like density in lower hemithorax Pericardial cyst or fat pad Posterior mediastinal mass Subpulmonic pleural effusion Lobar atelectasis Paralysis of hemidiaphragm Eventration of diaphragm Tumor of diaphragm Subphrenic mass effect Hernias

Eventration of diaphragm Size: typically 1/3 projected lung height Lateral view: anterior portion and dome ↑ Intact but thinned out muscle and tendon

Phrenic nerve paralysis Fluoroscopic “sniff” test or ultrasound dynamically assessfunction of muscle During a strong sniff, the paralyzed muscle will elevate while the normal muscle will depress

Tumor of diaphragm Mesothelioma Fibroma Lipoma Lymphoma Metastasis

Mass-like density in lower hemithorax Pericardial cyst or fat pad Posterior mediastinal mass Subpulmonic pleural effusion Lobar atelectasis Paralysis of hemidiaphragm Eventration of diaphragm Tumor of diaphragm Subphrenic mass effect Hernias

Subphrenic mass effect Hepatic tumors Hepatic abscess Hepatomegaly Ascites Bowel obstruction Pancreatic pseudocyst Pregnancy … Hepatic abscess

Hernias Hiatal hernia Bochdalek hernia Morgagni hernia Tramatic diaphragmatic rupture with hernia

Hiatal hernia Congenitally large esophageal orifice Retrocardiac air-containing masses Common finding in adult

Bochdalek hernia Maldevelopment / defective fusion of the cephalic fold of the pleuroperitoneal membranes Posterior pleuroperitoneal hiatus Primarily left-sided Congenital: left 80%, right 15%, bil. 5% Adult: left 66%, right 33% Majority contain fat only, less commonly kidney or bowel

Morgagni hernia Maldevelopment of septum transversum Anterior retrosternal or parasternal hiatus Primarily right-sided Majority contain omentum May contain bowel, most commonly colon

Traumatic rupture History of trauma but may be remote 90% left side, size vary Often contains bowel Stomach > colon > small bowel > omentum > spleen > kidney > pancreas

The END

Diaphragmatic hernia Bowel loops in chest Contralateral shift of mediastinum + heart Complete absence of diaphragm Absence of stomach, small bowel in abdomen