Question 1: Anterior Mediastinum
Stem: A 52-year-old woman is newly diagnosed with myasthenia gravis. A contrast-enhanced CT of the chest is performed for staging. It reveals a 3 cm, well-defined, homogeneous, soft-tissue mass in the anterior mediastinum, just anterior to the aortic root. The mass contains no fat or calcification.
Question: What is the most likely diagnosis?
(A) Teratoma (B) Retrosternal Goitre (C) Lymphoma (D) Thymoma (E) Pericardial Cyst
Correct Answer: (D) Thymoma.
Explanation:
- Why (D) is correct: The combination of an anterior mediastinal mass and a new diagnosis of myasthenia gravis (MG) is classic for a thymoma. Approximately 15% of patients with a thymoma have MG, and 30-40% of patients with MG have a thymoma. It is the most common primary tumour of the anterior mediastinum in adults.
- Why (A) is wrong: A teratoma is also in the anterior mediastinum but is typically a complex mass containing heterogeneous elements like fat, calcification, and cystic components.
- Why (B) is wrong: A retrosternal goitre would be seen in continuity with the thyroid gland in the neck and is often heterogeneous or has high attenuation from iodine.
- Why (C) is wrong: Lymphoma typically presents as a more bulky, lobulated mass, often involving multiple nodal stations or encasing vessels, rather than a single, well-defined mass.
- Why (E) is wrong: A pericardial cyst is a simple cyst (fluid-attenuation) and is most commonly found in the middle mediastinum, specifically the right cardiophrenic angle.
Key Points: Thymoma
- Location: Anterior mediastinum.
- Appearance: Typically a smooth, well-defined, homogeneous soft-tissue mass.
- Associations (Parathymic Syndromes):
- Myasthenia Gravis (most common).
- Pure red cell aplasia.
- Hypogammaglobulinaemia (Good syndrome).
Question 2: Anterior Mediastinum
Stem: A 25-year-old man undergoes a chest CT for a non-specific cough. The scan reveals a large, complex, encapsulated mass in the anterior mediastinum. The mass contains multiple densities, including areas of soft tissue, fluid, calcification, and macroscopic fat.
Question: What is the most likely diagnosis?
(A) Thymolipoma (B) Teratoma (C) Hodgkin’s Lymphoma (D) Morgagni Hernia (E) Thymic Carcinoid
Correct Answer: (B) Teratoma.
Explanation:
- Why (B) is correct: The presence of multiple tissue types (fat, soft tissue, fluid, calcification) within a single, well-defined anterior mediastinal mass is pathognomonic for a teratoma (a type of germ cell tumour).
- Why (A) is wrong: A thymolipoma is a rare tumour containing only mature adipose tissue (fat) and normal thymic tissue; it would not contain calcification or complex fluid.
- Why (C) is wrong: Lymphoma is a soft-tissue mass and does not contain fat or calcification (unless treated).
- Why (D) is wrong: A Morgagni hernia is an anterior diaphragmatic defect, which typically contains omental fat or loops of bowel, but not calcification or the complex appearance of a teratoma.
- Why (E) is wrong: A thymic carcinoid is a rare, solid, soft-tissue tumour that can be aggressive but would not contain fat.
Key Points: Mediastinal Teratoma
- Location: Anterior mediastinum.
- Pathology: A germ cell tumour containing elements from all three germ cell layers.
- CT Findings (Key): A complex, heterogeneous mass.
- Fat (the most specific finding).
- Calcification (e.g., teeth, bone).
- Fluid/Cystic components.
- “Floating globule sign”: Fat-fluid level.
Question 3: Anterior Mediastinum
Stem: A 28-year-old woman presents with a 2-month history of night sweats, fever, and weight loss (“B symptoms”). A CT scan of the chest shows a large, bulky, lobulated, and confluent soft-tissue mass in the anterior mediastinum, which appears to be encasing the great vessels.
Question: What is the most likely diagnosis?
(A) Hodgkin’s Lymphoma (B) Thymoma (C) Teratoma (D) Sarcoidosis (E) Retrosternal Goitre
Correct Answer: (A) Hodgkin’s Lymphoma.
Explanation:
- Why (A) is correct: The combination of “B symptoms,” a young patient, and a bulky, lobulated anterior mediastinal mass that involves multiple contiguous nodal groups is the classic presentation of Hodgkin’s Lymphoma (specifically, the nodular sclerosing subtype).
- Why (B) is wrong: A thymoma is typically a single, well-defined, non-invasive mass. It is not usually described as “bulky” or “confluent” in this way.
- Why (C) is wrong: A teratoma would be expected to contain fat or calcification.
- Why (D) is wrong: Sarcoidosis causes lymphadenopathy, but the nodes are typically discrete and well-defined (like “potatoes”), not a large confluent mass.
- Why (E) is wrong: A retrosternal goitre would be continuous with the thyroid gland.
Key Points: Mediastinal Lymphoma
- Location: Most commonly anterior mediastinum (Hodgkin’s) but can involve any nodal station.
- Appearance: Typically a large, lobulated, confluent soft-tissue mass involving multiple nodal groups.
- Presentation: Often seen in young adults; “B symptoms” (fever, night sweats, weight loss) are common.
- Subtype: Nodular Sclerosing Hodgkin’s Lymphoma is the most common cause of an anterior mediastinal mass from lymphoma.
Question 4: Anterior Mediastinum
Stem: A 68-year-old woman with a neck swelling presents with mild dysphagia. A CT scan of the neck and chest reveals a large, heterogeneous mass with several calcifications. The mass is seen to be in direct continuity with the left lobe of the thyroid gland and extends inferiorly into the anterior mediastinum, displacing the trachea to the right.
Question: What is the most likely diagnosis?
(A) Lymphoma (B) Aortic Arch Aneurysm (C) Thymoma (D) Oesophageal Carcinoma (E) Retrosternal Goitre
Correct Answer: (E) Retrosternal Goitre.
Explanation:
- Why (E) is correct: The key diagnostic feature is continuity with the thyroid gland. A mass extending from the neck into the mediastinum that is clearly part of the thyroid is a retrosternal goitre. They are often heterogeneous, can calcify, and avidly enhance due to their iodine content (appearing high-density even on non-contrast scans).
- Why (A) is wrong: Lymphoma would not be continuous with the thyroid gland.
- Why (B) is wrong: An aneurysm would be a vascular structure, enhancing with blood pool, and would arise from the aorta, not the thyroid.
- Why (C) is wrong: A thymoma is a primary mediastinal mass, separate from the thyroid.
- Why (D) is wrong: Oesophageal carcinoma is a posterior mediastinal pathology.
Key Points: Retrosternal Goitre
- Location: Arises from the neck, extends into the anterior (most common) or posterior mediastinum.
- Key Findings:
- Continuity with the cervical thyroid gland (the definitive sign).
- High attenuation on non-contrast CT (due to iodine content).
- Avid, heterogeneous enhancement.
- Often causes significant tracheal deviation.
Question 5: Middle Mediastinum
Stem: A 45-year-old man is found to have an incidental abnormality on a chest X-ray. A follow-up CT demonstrates a 3 cm, well-defined, unilocular mass with simple fluid attenuation (10 Hounsfield Units). It is located in the subcarinal region and does not enhance with contrast.
Question: What is the most likely diagnosis?
(A) Bronchogenic Cyst (B) Oesophageal Duplication Cyst (C) Pericardial Cyst (D) Saccular Aneurysm (E) Lymphadenopathy
Correct Answer: (A) Bronchogenic Cyst.
Explanation:
- Why (A) is correct: A simple fluid-attenuation cyst in the subcarinal region is the classic location and appearance of a bronchogenic cyst. The paratracheal region is the second most common location.
- Why (B) is wrong: An oesophageal duplication cyst is a posterior mediastinal structure, typically embedded within the wall of the oesophagus.
- Why (C) is wrong: A pericardial cyst is also a simple cyst but has a classic location in the middle or anterior mediastinum, most commonly the right cardiophrenic angle.
- Why (D) is wrong: A saccular aneurysm would be a vascular outpouching and would enhance intensely with contrast (i.e., be blood pool attenuation, >100 HU).
- Why (E) is wrong: Lymphadenopathy is solid soft-tissue attenuation (typically 40-60 HU) and would enhance.
Key Points: Bronchogenic Cyst
- Location: Middle mediastinum. Most common site is subcarinal, followed by paratracheal.
- Pathology: A congenital cyst from abnormal budding of the tracheobronchial tree.
- CT Findings:
- Smooth, well-defined, unilocular cyst.
- Usually water/fluid attenuation (0-20 HU).
- Can be high-attenuation if it contains proteinaceous or haemorrhagic material, but still will not enhance.
Question 6: Middle Mediastinum
Stem: A 50-year-old asymptomatic woman has a chest X-ray showing a well-defined mass at the right heart border. A CT scan confirms a 4 cm, thin-walled, unilocular, water-attenuation (5 Hounsfield Units) mass located in the right cardiophrenic angle, separate from the diaphragm.
Question: What is the most likely diagnosis?
(A) Morgagni Hernia (B) Lipoma (C) Bronchogenic Cyst (D) Pericardial Cyst (E) Lymphadenopathy
Correct Answer: (D) Pericardial Cyst.
Explanation:
- Why (D) is correct: The right cardiophrenic angle is the classic, textbook location for a pericardial cyst (a congenital coelomic cyst). Its appearance as a simple, thin-walled, water-attenuation cyst confirms the diagnosis.
- Why (A) is wrong: A Morgagni hernia is also in the anterior cardiophrenic angle but is a defect in the diaphragm and would contain omental fat or loops of bowel.
- Why (B) is wrong: A lipoma would be fat attenuation (-50 to -100 HU), not water attenuation.
- Why (C) is wrong: A bronchogenic cyst is a simple cyst, but its typical location is subcarinal or paratracheal, not in the cardiophrenic angle.
- Why (E) is wrong: Lymphadenopathy is solid soft-tissue attenuation, not cystic.
Key Points: Pericardial Cyst
- Location: Middle mediastinum (though often abuts the anterior).
- Classic Site: Right cardiophrenic angle (~70% of cases).
- CT Findings:
- Thin-walled, unilocular, non-enhancing cyst.
- Simple water attenuation (0-20 HU).
- Does not communicate with the pericardial sac.
Question 7: Middle Mediastinum
Stem: A 38-year-old woman presents with a persistent dry cough and painful, red nodules on her shins (erythema nodosum). Her chest X-ray demonstrates bilateral, symmetric hilar lymphadenopathy and right paratracheal lymphadenopathy.
Question: What is the most likely diagnosis?
(A) Tuberculosis (TB) (B) Metastatic Breast Cancer (C) Sarcoidosis (D) Hodgkin’s Lymphoma (E) Silicosis
Correct Answer: (C) Sarcoidosis.
Explanation:
- Why (C) is correct: The combination of bilateral, symmetric hilar adenopathy (often with right paratracheal involvement – the “1-2-3 sign” or “Garland’s triad”) is the classic radiographic presentation of Stage 1 Sarcoidosis. The clinical finding of erythema nodosum (Löfgren syndrome) makes this diagnosis highly likely.
- Why (A) is wrong: TB typically causes asymmetric hilar adenopathy, often with consolidation or a Ghon focus.
- Why (B) is wrong: Metastases also cause asymmetric adenopathy.
- Why (D) is wrong: Lymphoma can present this way, but the adenopathy is often bulkier, more confluent, and less perfectly symmetric. Sarcoidosis is the classic cause of symmetric adenopathy.
- Why (E) is wrong: Silicosis causes hilar adenopathy that classically has “eggshell” calcification, which was not described.
Key Points: Sarcoidosis (Mediastinal)
- Pathology: A multisystem granulomatous disease.
- Classic Finding: Bilateral, symmetric hilar lymphadenopathy.
- “1-2-3 Sign” (Garland’s Triad): Involvement of right paratracheal, right hilar, and left hilar nodes.
- Löfgren Syndrome: A specific acute presentation of sarcoidosis, consisting of hilar adenopathy, erythema nodosum, and polyarthralgia.
Question 8: Posterior Mediastinum
Stem: A 50-year-old man with a history of neurofibromatosis type 1 (NF-1) has a CT scan for an unrelated reason. The scan reveals a 3 cm, well-defined, homogeneous, soft-tissue mass in the left paravertebral sulcus at the level of T6. The mass is seen extending into and widening the adjacent neural foramen.
Question: What is the most likely diagnosis?
(A) Lymphoma (B) Neurogenic Tumour (e.g., Schwannoma) (C) Oesophageal Duplication Cyst (D) Extramedullary Haematopoiesis (E) Descending Aortic Aneurysm
Correct Answer: (B) Neurogenic Tumour (e.g., Schwannoma).
Explanation:
- Why (B) is correct: This is the classic “dumbbell tumour.” A mass in the posterior mediastinal paravertebral sulcus that widens a neural foramen is a neurogenic tumour (schwannoma or neurofibroma) until proven otherwise. The history of NF-1, which is strongly associated with neurofibromas, makes this diagnosis virtually certain.
- Why (A) is wrong: Lymphoma can involve paravertebral nodes but does not typically cause the classic neural foramen widening.
- Why (C) is wrong: An oesophageal duplication cyst is located adjacent to the oesophagus, not in the paravertebral sulcus.
- Why (D) is wrong: Extramedullary haematopoiesis is also paravertebral but is typically bilateral, lobulated, and does not erode bone or widen foramina.
- Why (E) is wrong: An aneurysm would be a vascular structure arising from the aorta.
Key Points: Neurogenic Tumours
- Location: Posterior mediastinum (most common cause of a mass here).
- Types: Schwannoma (most common), Neurofibroma, Ganglioneuroma.
- Key Findings:
- Round, well-defined mass in the paravertebral sulcus.
- Widening of the neural foramen (the “dumbbell sign”).
- Association: Neurofibromatosis Type 1 (NF-1).
Question 9: Posterior Mediastinum
Stem: A 42-year-old man with known beta-thalassemia major undergoes a CT scan for chest pain. The scan reveals bilateral, well-defined, lobulated soft-tissue masses in the lower thoracic paravertebral regions. There is no associated bone erosion or widening of the neural foramina.
Question: What is the most likely diagnosis?
(A) Neurofibromas (B) Lymphoma (C) Extramedullary Haematopoiesis (D) Oesophageal Varices (E) Bilateral Neurenteric Cysts
Correct Answer: (C) Extramedullary Haematopoiesis.
Explanation:
- Why (C) is correct: In a patient with a severe chronic haemolytic anaemia (like thalassemia or sickle cell disease), bilateral, lobulated, paravertebral masses are the classic appearance of extramedullary haematopoiesis (i.e., the body is making blood cells outside of the bone marrow).
- Why (A) is wrong: Neurofibromas are typically more focal, not bilateral and lobulated, and would be expected to widen the neural foramina.
- Why (B) is wrong: Lymphoma is possible but is less likely to be this symmetric and well-defined in the paravertebral space. The history of thalassemia strongly points to (C).
- Why (D) is wrong: Oesophageal varices are enlarged veins around the oesophagus and would appear as enhancing, serpiginous structures.
- Why (E) is wrong: Neurenteric cysts are rare, cystic, and associated with vertebral anomalies.
Key Points: Extramedullary Haematopoiesis
- Pathology: Proliferation of haematopoietic tissue outside the bone marrow, as compensation for severe chronic anaemia.
- Associations: Beta-thalassemia, Sickle Cell Disease, Hereditary Spherocytosis.
- CT Findings:
- Bilateral, lobulated, soft-tissue masses.
- Location: Classically paravertebral in the lower thorax.
- No bone erosion.
Question 10: Posterior Mediastinum
Stem: A 70-year-old man with a long history of GORD (gastro-oesophageal reflux disease) presents with dysphagia. A CT scan shows a large, retrocardiac mass containing air-fluid levels and oral contrast, which is seen herniating through the oesophageal hiatus of the diaphragm into the posterior mediastinum.
Question: What is the most likely diagnosis?
(A) Achalasia (B) Hiatus Hernia (C) Bochdalek Hernia (D) Oesophageal Duplication Cyst (E) Oesophageal Carcinoma
Correct Answer: (B) Hiatus Hernia.
Explanation:
- Why (B) is correct: The description of a portion of the stomach (containing air, fluid, and contrast) herniating through the oesophageal hiatus into the posterior mediastinum is the definition of a hiatus hernia.
- Why (A) is wrong: Achalasia is a massively dilated, fluid-filled oesophagus due to failure of the lower sphincter, but the stomach remains in the abdomen.
- Why (C) is wrong: A Bochdalek hernia is a posterolateral diaphragmatic defect (not at the hiatus) and typically contains fat, kidney, or spleen.
- Why (D) is wrong: This is a simple cyst within the oesophageal wall and would not contain air or oral contrast.
- Why (E) is wrong: Oesophageal carcinoma is an irregular, soft-tissue thickening of the oesophageal wall, which would cause narrowing, not herniation of the stomach.
Key Points: Hiatus Hernia
- Location: Posterior mediastinum.
- Pathology: Herniation of abdominal contents (most commonly the stomach) through the oesophageal hiatus.
- Types:
- Type 1 (Sliding): Most common (90%). The GEJ slides up into the chest.
- Type 2 (Rolling/Para-oesophageal): The GEJ is in a normal position, but the gastric fundus “rolls” up alongside it.
Question 11: Posterior Mediastinum
Stem: A 65-year-old man presents with dysphagia to both solids and liquids. A CT scan with oral contrast shows a massively dilated thoracic oesophagus that is filled with fluid and food debris. At the gastro-oesophageal junction, there is a smooth, symmetric, tapered narrowing known as the “bird’s beak” sign.
Question: What is the most likely diagnosis?
(A) Oesophageal Carcinoma (B) Scleroderma (C) Achalasia (D) Oesophageal Varices (E) Hiatus Hernia
Correct Answer: (C) Achalasia.
Explanation:
- Why (C) is correct: This is the classic CT and fluoroscopic description of achalasia. The cause is a failure of the lower oesophageal sphincter (LES) to relax, leading to proximal obstruction, massive dilatation, and the “bird’s beak” sign at the LES.
- Why (A) is wrong: Oesophageal carcinoma would cause an irregular, asymmetric, or shouldered narrowing, not a smooth, symmetric taper.
- Why (B) is wrong: Scleroderma also causes a dilated, aperistaltic oesophagus, but the LES is typically patulous (wide open), leading to severe reflux, not obstruction.
- Why (D) is wrong: Varices are dilated submucosal veins and do not cause obstruction or massive dilatation of the entire oesophagus.
- Why (E) is wrong: A hiatus hernia is a displacement of the stomach, not a functional obstruction of the oesophagus.
Key Points: Achalasia
- Pathology: A primary oesophageal motility disorder; failure of LES relaxation and aperistalsis.
- Presentation: Dysphagia to both solids and liquids.
- Imaging Findings:
- “Bird’s Beak” Sign: Smooth, tapered narrowing at the GEJ.
- Massive dilatation of the oesophageal body.
- Absence of a normal gastric air bubble.
Question 12: Posterior Mediastinum
Stem: A 6-month-old infant is being investigated for scoliosis. A CT of the spine reveals an anterior hemivertebra at T5. Adjacent to this, in the posterior mediastinum, is a 2 cm, well-defined, fluid-attenuation cyst.
Question: Given this combination of findings, what is the most likely diagnosis for the cyst?
(A) Oesophageal Duplication Cyst (B) Neurenteric Cyst (C) Bronchogenic Cyst (D) Extralobar Sequestration (E) Cystic Neuroblastoma
Correct Answer: (B) Neurenteric Cyst.
Explanation:
- Why (B) is correct: The combination of a posterior mediastinal cyst and an associated vertebral body anomaly (hemivertebra, butterfly vertebra, spina bifida) is pathognomonic for a neurenteric cyst. This is due to their shared embryological origin from an abnormal connection between the foregut and neural tube.
- Why (A) is wrong: An oesophageal duplication cyst is in the oesophageal wall but is not associated with vertebral anomalies.
- Why (C) is wrong: A bronchogenic cyst is in the middle mediastinum (subcarinal/paratracheal) and is not associated with vertebral anomalies.
- Why (D) is wrong: A sequestration is abnormal lung tissue with a systemic arterial supply.
- Why (E) is wrong: A neuroblastoma is a solid, often calcified, malignant tumour, not a simple cyst.
Key Points: Neurenteric Cyst
- Location: Posterior mediastinum.
- Pathology: A rare congenital cyst from a persistent neurenteric canal.
- Key Diagnostic Feature: The combination of a posterior mediastinal cyst and an adjacent congenital vertebral anomaly.
Question 13: Anterior Mediastinum
Stem: A 30-year-old woman is being treated for stage II Hodgkin’s lymphoma with chemotherapy. A baseline CT showed a bulky anterior mediastinal mass. A CT scan 6 months after completion of therapy shows the mass is gone, but the anterior mediastinal tissue, while smaller, still appears “full” for her age.
Question: This appearance of the thymus is best described as:
(A) Thymoma (B) Rebound Hyperplasia (C) Thymic Carcinoma (D) Lymphoid Hyperplasia (E) Thymolipoma
Correct Answer: (B) Rebound Hyperplasia.
Explanation:
- Why (B) is correct: Rebound hyperplasia is the regrowth of the thymus following a period of stress, such as chemotherapy, radiation, or major illness. The thymus, which shrinks during the stress (atrophy), “rebounds” and can appear diffusely enlarged, but it maintains its normal shape and should not have a focal mass.
- Why (A) is wrong: A thymoma is a focal, discrete tumour.
- Why (C) is wrong: This is an aggressive, invasive soft-tissue mass.
- Why (D) is wrong: Lymphoid hyperplasia is also a diffuse enlargement but is associated with autoimmune diseases (like myasthenia gravis or Grave’s disease), not post-chemotherapy status.
- Why (E) is wrong: This is a rare, fat-containing tumour.
Key Points: Thymic Hyperplasia
- Rebound Hyperplasia: Diffuse, symmetric enlargement of the thymus after a period of stress (e.g., chemotherapy, burns, surgery). The key is the clinical context.
- Lymphoid (Follicular) Hyperplasia: Diffuse enlargement associated with autoimmune diseases (MG, SLE, Grave’s).
Question 14: Posterior Mediastinum
Stem: A 75-year-old man presents with chest pain and a widened mediastinum on his chest X-ray. A CT angiogram reveals a 5.5 cm dilatation of the descending thoracic aorta, just distal to the left subclavian artery. There is high-attenuation “crescent” sign in the aortic wall, and a small left-sided pleural effusion.
Question: These findings are most concerning for what diagnosis?
(A) Stable Descending Aortic Aneurysm (B) Aortic Dissection (Stanford Type B) (C) Impending Aneurysmal Rupture (D) Oesophageal Carcinoma (E) Neurogenic Tumour
Correct Answer: (C) Impending Aneurysmal Rupture.
Explanation:
- Why (C) is correct: While this is an aneurysm, the presence of “high-attenuation crescent” sign within the aneurysmal wall is a key finding. This represents an acute intramural haematoma (blood within the wall) and is a sign of an unstable aneurysm with impending rupture. The adjacent pleural effusion (likely a small haemothorax) further supports this.
- Why (A) is wrong: A stable aneurysm would not have a high-attenuation crescent or an associated pleural effusion.
- Why (B) is wrong: A dissection would show an intimal flap separating a true and false lumen. An intramural haematoma is a variant of dissection, but “impending rupture” is the more specific and urgent diagnosis given the crescent sign.
- Why (D) & (E) are wrong: These are solid tumours and would not have this vascular appearance.
Key Points: Unstable Aortic Aneurysm
- Location: Can be ascending, arch, or descending.
- Signs of Impending Rupture:
- High-attenuation crescent sign: Acute haematoma in the wall/thrombus.
- Draped aorta sign: The posterior wall of the aorta bulges and conforms to the adjacent vertebral body.
- Focal discontinuity in the wall calcification.
- Associated pleural effusion (haemothorax).
Question 15: Anterior/Middle Mediastinum
Stem: A 60-year-old asymptomatic man has a CT scan that shows a 6 cm mass in the right cardiophrenic angle. The mass has a thin wall and is composed almost entirely of fat attenuation tissue (-80 Hounsfield Units). A few small vessels are seen coursing through it.
Question: What is the most likely diagnosis?
(A) Pericardial Cyst (B) Lipoma (C) Morgagni Hernia (D) Diaphragmatic Liposarcoma (E) Thymolipoma
Correct Answer: (C) Morgagni Hernia.
Explanation:
- Why (C) is correct: The most common content of an anterior (Morgagni) hernia is omental fat. Therefore, a fat-attenuation mass in the anterior cardiophrenic angle is most likely a Morgagni hernia. Small vessels (the omental vasculature) are commonly seen within it.
- Why (A) is wrong: A pericardial cyst is water attenuation (0-20 HU), not fat.
- Why (B) is wrong: A lipoma is also fat attenuation, but it is a true tumour. A hernia containing omental fat is far more common in this specific location.
- Why (D) is wrong: Liposarcoma is a malignant fat-containing tumour. It is very rare and would typically have thick septa, nodular soft-tissue components, and an invasive appearance.
- Why (E) is wrong: A thymolipoma is a fat-containing tumour, but it arises from the thymus and is located in the prevascular anterior mediastinum, not typically sitting directly in the cardiophrenic angle.
Key Points: Morgagni Hernia
- Location: Anterior mediastinum, in the cardiophrenic angle (more common on the right).
- Pathology: A congenital diaphragmatic hernia through the foramen of Morgagni.
- CT Findings:
- Fat-attenuation mass (herniated omentum) in the cardiophrenic angle.
- Can also contain bowel loops (less common).
- Vessels can be seen draping through the fat.
