1. 90 Fatty Lesions in the
Abdomen and Pelvis on
Computed Tomography

2. CLINICAL IMAGAGING
AN ATLAS OF DIFFERENTIAL DAIGNOSIS
EISENBERG
DR. Muhammad Bin Zulfiqar
PGR-FCPS III SIMS/SHL

3. • Fig GI 90-1 Hepatic angiomyolipoma. Well-
defined oval mass (arrow) with an attenuation
value of fatty tissue (-57 H) in a woman with
an echogenic nodule suggestive of
hemangioma detected on ultrasound.199

4. • Fig GI 90-2 Focal fatty infiltration of the
pancreas. Hypoattenuating pancreatic mass
(arrow) that does not deform the border and
has typical fatty density.199

5. • Fig GI 90-3 Lipoma of the pancreas. Large,
homogeneous, fat-attenuation mass within
the pancreatic head (arrows) with lateral
displacement of the common bile duct
(arrowhead).200

6. • Fig GI 90-4 Pancreatic lipomatosis. Complete
replacement of the parenchyma by fatty tissue with
marked glandular atrophy. Note the dense acini
(arrows) separated by increased fatty tissue.199

7. • Fig GI 90-5 Fatty replacement of the pancreas. In
a patient with cystic fibrosis, pancreatic tissue is
virtually completely replaced by tissue with fat
attenuation (arrowheads). Note the thin linear
density of the main pancreatic duct.200

8. • Fig GI 90-6 Colonic lipoma. Characteristic fat-
attenuation mass (arrow) in the proximal part
of the transverse colon.199

9. • Fig GI 90-7 Epiploic appendagitis. Ovoid mass of fat attenuation (open arrow)
anterior to the descending colon. The mass is surrounded by a hyperattenuating
rim. A central high-attenuation dot was seen on images obtained superiorly (not
shown). Note the moderate fat stranding (arrowhead) and the mild focal
thickening of the adjacent colonic wall (solid arrow).200

10. • Fig GI 90-8 Intussusception led by a lipoma.
(A) Small amount of mesenteric fat between
the walls of the intussusceptum and the
intussuscipiens (arrows). (B) More superior
image shows a leading lipoma (arrowhead).200

11. • Fig GI 90-9 Mesenteric panniculitis. Discrete
increase (arrowheads) in density of fatty tissue
surrounding mesenteric vessels without evidence
of vascular displacement. Note the thin halo of
normal fatty tissue surrounding the mesenteric
vessels.199

12. • Fig GI 90-10 Cavitating mesenteric lymph node
syndrome. Multiple, round, fluid-attenuation
masses with thin walls (arrows) in the mesentery.
Some of the masses have lower attenuation
values (arrowheads), indicating the presence of
fatty material.199

13. • Fig GI 90-11 Omental infarction. Inhomogeneous,
round, high-attenuation fatty mass in the greater
omentum (arrows). The mass is anterior to the
ascending colon and exerts mass effect on it.
There is mild adjacent wall thickening
(arrowhead).200

14. • Fig GI 90-12 Inguinal hernia. Well-defined fatty
mass within the inferior aspect of the right
inguinal canal (arrow), representing herniation of
intra-abdominal fat.200

15. • Fig GI 90-13 Adrenal myelolipoma. Large,
heterogeneous right adrenal mass (long
arrow) with a more dense area in the center
(short arrow) and fatty attenuation (-102 H) in
the periphery.199

16. • Fig GI 90-14 Adrenal myelolipoma. (A) Well-
defined mass with predominantly soft-tissue
attenuation in the left adrenal gland. Note the
nodule of fat attenuation (arrow). (B) In another
patient, a contrast scan shows a heterogeneous
mass (arrows) with fatty and enhancing soft-
tissue components. The presence of fat permits a
reliable diagnosis of a benign myelolipoma
despite the soft-tissue elements.200

17. Fig GI 90-15 Adrenal adenoma. Low-attenuation mass in the left
adrenal gland (arrow).200

18. • Fig GI 90-16 Renal angiomyolipoma. Heterogeneous mass in the
lateral portion of the left kidney. The mass is predominantly of soft-
tissue attenuation and resembles a renal cell carcinoma. However,
the presence of focal areas of fat attenuation (arrows) permits
confident diagnosis of an angiomyolipoma.200

19. • Fig GI 90-17 Bilateral renal angiomyolipomas.
Bilateral low-attenuation masses (long arrows)
projecting to the perinephric space in this patient
with tuberous sclerosis. Note the serpentine
vascular structures (short arrows) located within
the lesions.199

20. • Fig GI 90-18 Renal lipoma. Mass of completely
homogeneous fatty density on this contrast
image. Note the absence of vessels and tissue
within the lesion, which differentiates this
appearance from angiomyolipoma.199

21. • Fig GI 90-19 Renal sinus lipomatosis. Extensive
fatty deposition in the left renal sinus (arrow)
that surrounds and compresses the collecting
system. The thickness of the renal
parenchyma is slightly reduced (arrowheads).
Of incidental note are thin calcifications in the
gallbladder.199

22. • Fig GI 90-20 Replacement lipomatosis.
Generous fatty infiltration (arrow) of both the
right renal parenchyma and perinephric space.
Note the calcified staghorn calculus (*) in the
renal pelvis.199

23. • Fig GI 90-21 Ovarian teratoma. Large mass
containing components of the three germ layers.
It consists of low-attenuation fatty tissue (straight
arrow), teeth (curved arrow), and structures with
attenuation similar to that of the abdominal
musculature (arrowheads).199

24. • Fig GI 90-22 Ovarian lipoma. Well-defined
tumor in the right adnexal region that has
smooth margins (arrow) and the attenuation
of fat.199

25. • Fig GI 90-23 Retroperitoneal liposarcoma. There is a
huge tumor mass (long arrows) with heterogeneous
fatty attenuation that has septa (short arrows) and
well-defined lobular contours. There is mass effect on
adjacent structures, such as the left kidney, but no
evidence of infiltration.199

26. • Fig GI 90-24 Retroperitoneal liposarcoma. The
coarse, thickened septa (arrow) in this
heterogeneous, fat-attenuation mass are
suggestive of a well-differentiated tumor.200