Read first the text book: Computed Tomography and Magnetic resonance of
the Thorax by Nadich et all
Then go through this exercise to assess your comprehension
Fat has a low CT Hounsefield numbers -70 to -130 and are easily recognized.
Fat is normally present in mediastinum and helps in delineation of structures.
Q. What are the fatty lesions in the mediastinum?
Answer
Q. What are the fatty lesions in the mediastinum?
- Lipomatosis
- Lipoma
- Tran diaphragmatic hernias
- Germ cell tumors
Q. What are the characteristics of Mediastinal lipomatosis:
Answer
Q. What are the characteristics of Mediastinal lipomatosis:
- Abundant amounts of fat in mediastinum and
pleuropericardiac angles
- Unencapsulated
- Mediastinal widening in CXR smooth and symmetric extends
from inlet to hila
- Convex bulging of pleuromediastinal interfaces in CT
- No compression or displacement of structures
- Homogenously lucent
Q: When do you encounter Mediastinal lipomatosis?
Answer
Q: When do you encounter Mediastinal lipomatosis?
- Associated with Cushing's syndrome
- Benign
Q: What does inhomogeneity of Mediastinal lipomatosis
suggest?
Answer
Q: What does inhomogeneity of Mediastinal lipomatosis
suggest?
In homogeneity suggests
- Mediastnitis
- Hemorrhage
- Tumor infiltration
- Post radiation fibrosis
- Post surgical changes
Q. What are the types of fatty hernias
Answer
Q. What are the types of fatty hernias
- Omental fat herniating through foramen of Morgagni leads to
cardiophrenic angle mass on right side.
- Omental vessels can be seen as fine linear densities.
- Fat herniation through foramen of Bochdalek occurs on left side .
- Herniation through phrenicoesophageal membrane presents as widened Para spinal
line and retorcardiac mass.
Q. What are the CT characteristics of Lipoma
Answer
Q. What are the CT characteristics of Lipoma
- No compression unless very large
- Homogenous with low CT numbers
- May or may not be capsulated
- Boundaries are smooth and sharply defined
- Difficult to distinguish Liposarcoma from Lipoma by CT
Q: List fatty lesions other than Lipoma and Hernias
and their location.
Answer
Q. List fatty lesions other than Lipoma and Hernias
and their location.
- Thymo-lipoma: Inhomogeneous fatty mass in the anterior mediastinum
- Spinal lipoma in posterior mediastinum
- Angio-lipoma in posterior mediastinum
- Fatty transformation of extramedullary hematopoiesis
- Germ cell tumors in anterior mediastinum
Q. List Germ cell tumors
Answer
Q. List Germ cell tumors
- Dermoid cyst
- Teratoma
- Seminoma
- Embryonal carcinoma
- Choriocarcinoma
Q. What is the genesis of Germ cell tumors
Answer
Q. What is the genesis of Germ cell tumors
- Arrested embryological migration of primitive germ cells in the mediastinum
- Second to fourth decade of life
- Dermoid cysts contain elements of the ectodermal layer of germ cells only
- Benign teratomas contain elements of all germinal layers
Q. What are the CT characteristics of Germ cell tumors
Answer
Q. What are the CT characteristics of Germ cell tumors
- Commonly found in anterior mediastinum
- Well demarcated
- Encapsulation is the rule
- Calcification, fat and soft tissue can be recognized (pleomorphic appearance)
- Fat fluid level is diagnostic
Q: How do you recognize malignant germ cell tumors?
Answer
Q: How do you recognize malignant germ cell tumors?
- Malignant lesions are poorly defined
- Ttumor molds and compresses
surrounding structures
Q: Thymolipoma
- Benign neoplasm of fatty tissue within thymus
- asymtomatic
- Large, yellowish soft pliable
- Histologically adipose tissue with areas of thymic tissue
- Radiologically near the junction of heart and great vessels
- Tend to displace heart and great vessels
- Tends to slump towards diaphragm
The session is over