The diagnosis of retroperitoneal lesions is challenging which includes lesions from the retroperitoneal organs and lesions outside the major organs. To differentiate and diagnose retroperitoneal lesions and Intraperitioneal lesions based on signs on MDCT. To demonstrate various signs on MDCT to differentiate lesions from the retroperitoneal organs and primary retroperitoneal lesions. To present an approach for the diagnosis of retroperitoneal lesions on MDCT.

Introduction The retro peritoneum is the portion of the abdomen located posterior to the peritoneal cavity extending from the diaphragm to the pelvic inlet . It includes portions of the colon, duodenum, pancreas, kidneys, adrenal glands, abdominal aorta, inferior vena cava, lymph nodes, fat and much of the abdominal wall musculature. The retro peritoneum is commonly divided into three spaces by the anterior and posterior renal fasciae: 1. Anterior pararenal space 2. Perirenal space 3. Posterior pararenal space Psoas compartment is sometimes considered a fourth...

We retrospectively studied 25 patients with abdominal mass lesions and subsequently confirmed with surgical and histopathological diagnoses of retroperitoneal and intraperitoneal (IP) mass lesions. The cases included were retroperitoneal sarcomas, renal cell carcinoma, suprarenal lesions, mesenteric mass and GIST. Approach to retroperitoneal (RP) lesions: Step 1. Intraabdominal or Retroperitoneal (figure 5) Ø The retroperitoneal lesion due to its location tends to show mass effect on the adjacent retroperitoneal structures. Ø Lateral or anterior displacement of the retroperitoneal structures or compression over the retroperitoneal structures. Case...

Reliable differentiation between intra and retroperitoneal lesions can be made using a specific approach pattern and various MDCT signs.

Dr Vidya Bhargavi, Resident, Department of radiology, Vydehi institute of medical sciences, Bangalore, India. Dr Rohini Avantsa, MD. Sectional ImagingDivision, Department of radiology, Vydehi institute of medical sciences, Bangalore, India. [email protected] Dr Prachi Kala, MD. Sectional ImagingDivision, Department of radiology, Vydehi institute of medical sciences, Bangalore, India.

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