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1. APPROACH TO
RETROPERITONEAL MASS
MODERATOR: Dr. P. MANASA,MD
Assistant professor
PRESENTER : Dr. Aasritha K

3. • The FIRST STEP is to decide whether the tumor is located within the
retroperitoneal space.
• Displacement of normal anatomic structures.
• Anterior displacement of retroperitoneal organs (eg, kidneys, adrenal glands,
ureters, ascending and descending colon, pancreas, portions of the duodenum)
and major vessels and some of their branches strongly suggests that the tumor
arises in the retroperitoneum.
• Some radiological signs that are helpful in determining tumor origin include
• BEAK SIGN
• PHANTOM ORGAN SIGN
• EMBEDDED ORGAN SIGN
• PROMINENT FEEDING ARTERY SIGN

4. • “BEAK SIGN”- When a mass
deforms the edge of an adjacent
organ into a “beak” shape,it is
likely that the mass arises from
that organ . On the other hand,
an adjacent organ with dull
edges suggests that the tumor
compresses the organ but does
not arise from it.

6. • “PHANTOM ORGAN SIGN”-
• When a large mass arises from a
small organ, the organ
sometimes becomes
undetectable or invisible.

8. • “EMBEDDED ORGAN SIGN”
• A mass that arises from a given
organ often appears embedded
within and the interface between
the two may be difficult to
appreciate. Conversely, a mass
that abuts but does not originate
from a hollow structure
compresses it to produce a
crescentic deformity.

11. DD’S of Retroperitoneal mass

12. Primary Retroperitoneal Sarcomas
• They may develop at any age, but most present in the sixth and
seventh decades of life. They are often of high histologic grade and
have a mean size of 17 cm.
• In descending order of frequency, include
• liposarcoma (40%),
• leiomyosarcoma (30%), and
• malignant fibrous histiocytoma (MFH; 15%)

13. Liposarcoma
• Most common sarcomas of the retroperitoneum.
• 5th and 6th decades of life, slight female predilection.
• When the mass is somewhat irregular and ill-defined but contains fat,
the diagnosis of liposarcoma should be considered.
• They are classified at pathologically into well-differentiated,
pleomorphic, round cell , myxoid, and dedifferentiated types.
• Well-differentiated liposarcomas usually contain an appreciable
amount of fat, whereas high-grade liposarcomas may not
demonstrate appreciable fat, thereby appearing similar to other
sarcomas.

15. Leiomyosarcoma
• 2/3 - external to the lumen of the IVC, whereas
• 1/3 - both intraluminal and extraluminal components.
• Leiomyosarcoma is the m.c intraluminal venous neoplasm and is the most common
primary tumor of the IVC.
• The finding of a retroperitoneal mass that has both intraluminal and extraluminal
components is very suggestive of a leiomyosarcoma.
• IMAGING- leiomyosarcomas usually have attenuation similar to that of muscle,
• Low to intermediate signal intensity on T1-weighted imaging.
• Heterogeneous intermediate to high signal intensity on T2W imaging.
• Central liquefactive necrosis is more common and extensive than in others.
• Fat and calcification are not typically seen.

18. Malignant Fibrous Histiocytoma
• MFH accounts for 25% of all soft tissue sarcomas, but only 16% arise in the
retroperitoneum.
• Imaging- a large, relatively well circumscribed mass that spreads along fascial
planes and between muscle fibers, with attenuation similar to muscle.
• Low to intermediate signal intensity - T1
• Heterogeneously increased signal intensity on T2
• Intratumoral fat is absent. Cystic degeneration or necrosis may be present.
• The “bowl of fruit” sign is a mosaic of mixed low, intermediate, and high signal
intensity on T2-weighted imaging ,that correlates with the presence of
intratumoral solid components, cystic degeneration, hemorrhage, myxoid stroma,
and fibrous tissue.

20. LYMPHOMA
• M.C retroperitoneal malignancy.
• Nodal and extranodal lymphoma typically has homogeneous soft
tissue attenuation, even when large, because necrosis and
calcification before therapy are uncommon.
• Confluent lymphadenopathy on both sides of the superior mesenteric
vessels gives rise to an appearance described as the “sandwich sign.

22. Primary Retroperitoneal Extragonadal Germ Cell
Tumor
• IMAGING- primary retroperitoneal EGCTs are typically large (mean
size, 7 to 8 cm), MIDLINE -enhancing retroperitoneal masses of soft
tissue attenuation .
• A midline location of a retroperitoneal mass is probably the most
helpful finding to suggest this diagnosis, whereas metastatic
retroperitoneal lymphadenopathy from a primary testicular neoplasm
tends not to be in midline.

24. RETROPERITONEAL TERATOMA

25. PARAGANGLIOMA

26. ABDOMINAL AORTIC
ANEURYSM

27. Retroperitoneal fibrosis
• Most commonly idiopathic.
• RPF typically originates below the aortic bifurcation at the level of the
sacral promontory or lower lumbar vertebrae and then extends
superiorly along the anterior spinal surface in a periaortic and
pericaval distribution toward the renal hila, where it may rarely
surround the renal pelvis.
• Hydronephrosis, ureteral narrowing, slight medial ureteral
displacement, lack of anterior displacement of the aorta from the
lumbar spine helps differentiate from lymphoma.
• On CT, RPF has homogeneous soft tissue attenuation similar to or
slightly greater than that of skeletal muscle.

29. RETROPERITONEAL LYMPHADENOPATHY