Retroperitoneum

Question 1

What confines the anterior pararenal space?

Answer 1

Anterior renal fascia (Gerota’s)
Posterior renal fascia (Zuckerkandl)
Lateroconal Fascia

Question 2

What is contained within the anterior renal fascia?

Answer 2

Ascending and Descending colon
Duodenum and Pancreas (Pancreaticoduodenal Component)
Continuous across the midline

Question 3

What binds the posterior pararenal space?

Answer 3

Posterior renal fascia (anteriorly)
Transversalis Fascia (posteriorly)
- medially the psoas muscle limits
- laterally open toward the flank
- inferiorly open to the pelvis
» the posterior pararenal space contains fat

Question 4

Name differentials for cystic non-neoplastic processes in the retroperitoneum

Answer 4

Haematoma
Urinoma
Lymphocele
Seroma
Abscess

Pancreatic pseudocyst
Pancreatic or peripancreatic necrosis

Question 5

Describe the appearance of a retroperitoneal haematoma on CT and MRI?

Answer 5

Variable appearance

Question 6

What is a urinoma?

Answer 6

Question 7

What is a lymphocele?

Answer 7

Collection of lymph, contains no epithelial lining, can occur post-lymphadenectomy.

On CT homogenous, low attenuation. Fat can be seen.

Question 8

List differentials for solid non neoplastic processes?

Answer 8

Retroperitoneal fibrosis
IG4 Related Sclerosing Disease

Pseudotumoral
Lipomatosis

Histiocytosis

Extramedullary Haematopoesis

Amyloidosis

Question 9

Describe retroperitoneal fibrosis?

Answer 9

It is more often than not idiopathic ~ 70% of cases

Secondary causes include
- Drug-induced
- Inflammatory Aortic Aneurysm
- Traumatic (haematoma, urinoma, radiation, surgery)
- Infectious
- Granulomatous disorders
- Histiocytosis (Erdheim- Chester)
- Occupational

Neoplastic
- endometriosis
- amyloidsis

Question 10

What does retroperitoneal fibrosis look like on imaging?

Answer 10

Question 11

Differentials for Ig4 sclerosing disease in RP?

Answer 11

Question 12

What is extramedullary haematopoesis and what are the imaging features?

Answer 12

Question 13

What are the differentials for retroperitoneal tumours?

Answer 13

• Primary retroperitoneal Tumours
• Originating from retroperitoneal organs
• Metastasis

Question 14

Describe the four primary retroperitoneal tumors

Answer 14

• Mesodermal
• Germ cell
• Neurogenic
• Lymphoid

Question 15

Describe the different mesodermal retroperitoneal tumours.

Answer 15

Question 16

important features of a desmoid tumour?

Answer 16

Question 17

describe the different subtypes of liposarcoma and their imaging features?

Answer 17

Question 18

What is the most common primary IVC tumour?

Answer 18

Question 19

Describe a lymphangioma?

Answer 19

Question 20

Differentials for neurogenic retroperitoneal mass?

Answer 20

Question 21

Describe a schwannoma?

Answer 21

• small schwannomas are round and homogenous
• large schwannomas are heterogeneous, encapsulated and extend along nerves.

Question 22

Describe the features of a neurofibroma?

Answer 22

Question 23

What is a plexiform neurofibroma?

Answer 23

Neurogenic RP mass differential

Question 24

Describe paraganglioma?

Answer 24

Neurogenic RP mass differential

Question 25

describe germ cell tumor?

Answer 25

Question 26

Describe a teratoma? (included within differentials of germ cell tumour)

Answer 26

Question 27

Describe some diagnostic clues for retroperitoneal masses.

Answer 27

Question 28

Describe the pattern of spread for lesions that spread between structures.

Answer 28

Question 29

What retroperitoneal masses will contain fat?

Answer 29

Question 30

What RP masses contain myxoid strroma?

Answer 30

Question 31

What RP masses might you see tumour necrosis?

Answer 31

Question 32

important things to keep in mind about RP masses

Answer 32