Mediastinum Flashcards
How do you differentiate between benign and malignant thyroid masses on CT?
Benign - well defined, spherical or lobular, rounded or irregular well defined areas of calcification
Malignant - amorphous cloud like calcification
Name all types of thymic pathology with radiology features.
Thymomas - anterior to ascending aorta, spherical or oval, may contain cysts, may have calcification, punctate or curvilinear. 1.5 to 2cm. May invade medi fat. Homogenous density and uniform enhancement with contrast. High T1, high on T2.
Thymic CA - large heterogenous, areas of necrosis and calcification. Invade surrounding structures.
Thymic lymphoma - same as thymoma, generalized.
Thymic carcinoid - same as thymoma
Thymolipoma - fatty nature. Islands of thymus and fibrous septa through lesion.
Thymic hyperplasia - both lobes enlarged, uniformly. May mimic thymic mass.
Mature teratoma - cystic mostly, well defined lobulated or rounded mass. Anterior mediastinum. Occasional fat and calcification. Soft tissue components seen. Fat helpful in dx.
Malignant germ cell - lobular, asymmetrical mass. Medistainal fat may be obliterated. Tumours homogenous soft tissue or multiple areas of contrast enhancement.
What is the diff dx if hilar or mediastinal lymph nodes are more than 2cm long?
Mets, lymphoma, sarcoidosis, TB and fungal
How do the different types of lymph nodes appear on cxr?
Right paratracheal - widening of right paratracheal stripe
Azygos - displace vein laterally, shadow more than 10mm
Subaortic - bulge between aortic arch and main pulmonary artery
Hilar - enlargement/lobulation of outline hilarious shadow
Subcarinal - widens carina angle, displaces AO line, confused with L atrial enlargement
Posterior mediastinal - displacement of paraspinal and Paraoesophogeal line
What lymph nodes increase in leukaemia and lymphoma?
Anterior mediastinal and para tracheal. Also tracheobronchial and subcarinal. Bilateral but not symmetrical.
Hilar, posterior mediastinal, paracardiac rare
Foregut duplication cysts?
What is the diff DX of prevascular masses in the mediastinum?
Thyroid - follow from neck, superior in anterior mediastinum that deviates trachea
Thymic
GCT/teratomas
Lymphadenopathy
What is the diff DX of paracardiac masses?
In contact with diaphragm - Pericardial cyst, diaphragm hernia, fat pad, l.n
Separated - GCT, mesenchymal/pericardial tumours, cystic teratomas, thymic masses
What is the diff diagnosis of paratracheal, subcarinal and paraoesophageal masses?
L.n, thyroid mass, foregut cyst, oesophageal tumour, hiatus hernia, paraspinal mass and aortic aneurysms
What are the 2 most common causes of paravertebral masses?
Neurogenic lesions, neoplastic l.n
X-ray findings of mediastinitis.
Widening and lack of clarity of mediastinal outline next to oesophagus.
Streaks or round collections of air with possible air fluid levels.
Left sides pleural effusions.
Lower love pneumonia/atelectasis.
What are the x-ray findings of a pericardial effusion?
Increase in size of cardiac silhouette. Filling of retrosternal space, effacement of cardiac borders, water bottle cardiac configuration, bilateral hilar overlay
On lateral, epicardial fat pad sign positive. Anterior pericardial stripe thicker than 2mm.
