9%20ECOGRAFIA%20ABDOMINAL%20COMO%20CUANDO%20DONDE

212
ABDOMINAL ULTRASOUND
A
B
Figure 8.14 (A) Hypoechoic, caecal carcinoma. The eccentrically thickened bowel wall is demonstrated with a narrow,
hyperechoic lumen (arrow). (B) Caecal carcinoma presenting as a mass in the right iliac fossa.
OTHER RETROPERITONEAL
ABNORMALITIES
Ultrasound is successful in identifying retroperitoneal
masses, but CT and MRI are more effective
at establishing the extent and nature of many of
these masses, particularly those partly obscured by
gas-filled bowel.
The majority of malignant retroperitoneal
tumours are renal or adrenal in origin. Other primary
tumours, apart from lymphomas, are rare,
and include liposarcoma and leiomyosarcoma.
These tend to be large when they present, and of
variable/complex ultrasound appearance. Encasement
of major vessels by tumour is a further characteristic
of the retroperitoneal origin of the mass,
together with anterior displacement of structures
such as the pancreas, kidneys, aorta and IVC.
Ultrasound is also able to identify peritoneal and
omental deposits in patients with late-stage carcinoma.
These are particularly amenable to diagnosis
when surrounded by ascites (Fig. 8.16) and
usually arise from gynaecological or urological
tumours.
Benign retroperitoneal masses identifiable on
ultrasound include haematomas, psoas abscesses,
lymphadenopathy (Fig. 8.17) and pancreatic
pseudocysts.
Figure 8.15 Dilated, fluid-filled loops of bowel as a
result of an obstructing caecal carcinoma. Ascites is also
present.