[Intraabdominal focal fat infarction]

BACKGROUND

Intraabdominal focal fat infarction is an acute abdominal condition unfamiliar to many doctors. Until recently it has only been diagnosed perioperatively, but since 1985 several authors report the use of imaging modalities and a spontaneous regression of this disorder.

MATERIAL AND METHODS

Report of two cases and a review of the literature.

RESULTS

Intraabdominal focal fat infarction presents characteristic imaging findings with ultrasonography and computer tomography. A well-defined lesion of fat with oedema is found in the location of maximum tenderness.

INTERPRETATION

Doctors dealing with the acute abdomen, particularly radiologists and surgeons, should be aware of this condition. With a confident diagnosis, unnecessary surgery may be avoided.

Computed tomographic features of intraperitoneal fat-containing lesions: pictorial essay

Abdominal CT, which is a common imaging modality performed for a variety of clinical indications, provides an important tool in the diagnosis and evaluation of various lesions with fatty components affecting the peritoneal cavity and its contents.

Lymph node enlargement within the hepatoduodenal ligament in patients with chronic hepatitis C reflects the immunological cellular response of the host

BACKGROUND/AIMS

Lymph nodes in the hepatoduodenal ligament seem to be a common ultrasonographic finding in patients with chronic hepatitis C. Lymphadenopathic enlargement is associated with the histological hepatic features reflecting the immunological response of the host, but the correlation between lymphadenopathy, liver histology and the cellular immunoreactivity of the host has never been studied.

AIM

(1) To specify the prevalence of lymph nodes within the hepatoduodenal ligament; and (2) to investigate whether lymphadenopathies might reflect the immunological response of the host.

METHODS

One hundred and eleven patients were enrolled in this study. Eleven chronic hepatitis B patients and 34 healthy volunteers served as controls.

RESULTS

Lymph nodes were detectable in 90 out of the 104 chronic hepatitis C patients studied. After logistic regression, a high CD8 level and the absence of post hepatitis C cirrhosis were associated with lymph node enlargement. The total lymph node volume was correlated with transaminase levels, inflammatory activity, and stage of fibrosis.

CONCLUSIONS

(1) The prevalence of lymph nodes within the hepatoduodenal ligament is high; (2) lymph node enlargement is correlated with the immunological cellular response of the host; and (3) the total lymph node volume is correlated with hepatic necroinflammatory markers and the stage of fibrosis.

Supplemental transcatheter arterial chemoembolization through a collateral omental artery: treatment for hepatocellular carcinoma

PURPOSE

To evaluate the therapeutic efficacy and safety of supplemental transcatheter arterial chemoembolization (TACE) through the extrahepatic collateral omental artery (OA) for the treatment of hepatocellular carcinoma (HCC).

METHODS

We studied 21 patients with extrahepatic collaterals of the OA, among 1,512 patients with HCC who had undergone angiography. HCCs supplied by collateral OAs were located at: segment IV in seven, segment V in five, segment III in three, segment VI in three and segment VIII in three patients (Couinaud classification of segments). On preoperative CT scans, every HCC was abutting the liver surface. Adjacent omental infiltration or engorgement was noted in 11 patients. Celiac and hepatic arteriograms showed hypertrophy of the feeding OA in all patients. TACE of the OA was performed in 19 patients with an emulsion of iodized oil and doxorubicin hydrochloride. Embolization with gelatin sponge particles was added in five patients.

RESULTS

Collaterals of the OA to the HCC were found on the first to seventeenth sessions of TACE. On follow-up CT scans, five patients showed complete uptake of iodized oil in the tumor. Partial uptake of iodized oil was noted in 13 patients and no uptake in one patient. There was no serious complication that related to the omental embolization, such as omental or bowel ischemia. The cumulative survival rates from the time of the TACE of the OA were 81% at 6 months and 68% at 12 months.

CONCLUSION

TACE of the OA is safe and has a potential therapeutic effect in the treatment of HCC.

CT findings of omental torsion and infarction: case report and review of the literature

A 37-year-old woman presented with progressive diffuse abdominal pain. Computed tomography (CT) showed diffuse streaking of the greater omentum with a mass of fat density located anteriorly just below the umbilicus, showing a whirling pattern of concentric streaks. Surgery and pathology revealed torsion and infarction of the greater omentum. Because of its rarity and nonspecific clinical features, the diagnosis is seldom made preoperatively. We describe a patient with characteristic CT findings of omental torsion. Preoperative diagnosis is important since conservative management has been suggested.

Segmental infarction of the omentum: a difficult diagnosis

Segmental infarction of the greater omentum is a rare diagnosis. This report describes a case of omental torsion in an eight-year-old boy. The report assesses the predisposing factors, the classification and the place of ultrasonography.

Omental malignant fibrous histiocytoma with a unique rough endoplasmic reticulum inclusion

The laminated inclusions in the rough endoplasmic reticulum (RER) are peculiar structures seen only in some cases of chondrocytes of pseudoachondroplasia. These ultrastructurally unique organelles have not yet been reported in inflammatory malignant fibrous histiocytoma (MFH). We describe an omental mass showing unique laminated inclusions in the RER in a young man with intra-abdominal inflammatory MFH. The most striking ultrastructural feature was a dilated RER containing a fine granular substance and a more electron-dense material exhibiting an onion skin-like lamellated or maze-like pattern, mimicking that of so-called laminated inclusions. These lamellated inclusions occupied most of the cytoplasm of the tumor cells. We speculate that the ultrastructural finding of the laminated RER inclusion is not specific for cartilage cells, but may represent abnormal accumulation of some kind of glycoprotein material or matrix protein. This granular material may undergo organization to form a peculiar laminated structure, probably due to a metabolic or fixation process. Further study is needed to elucidate the nature of this material.

Heterotopic paragonimiasis in the omentum

Paragonimus westermani is a lung fluke but may be found in organs other than the lungs. A case of omental paragonimiasis was found incidentally by plain radiography and computed tomography and showed multiple, irregularly shaped, conglomerated calcifications in the intraperitoneum. Many P. westermani ova were detected in the resected omentum. This uncommon calcification on the plain abdominal radiography and computed tomography scan was considered to represent radiologic findings of ectopic paragonimiasis.

[Omental torsion: imaging techniques can prevent unnecessary surgical interventions]

INTRODUCTION

Segmentary infarction of the greater omentum produces a clinical profile of acute abdomen. To date, the cause has been discovered during surgery. Greater use of ultrasonography and computed tomography (CT) in the emergency department could lead to preoperative diagnosis. The aim of this study was to describe the advisability of avoiding surgery in selected patients.

PATIENTS AND METHOD

A series of nine adult patients (six men and three women), aged between 18 and 50 years, with a final diagnosis of primary omental torsion were reviewed. The first three patients underwent surgery: two underwent laparotomy for suspected acute appendicitis and the third underwent laparoscopy with a diagnosis of non-specific acute abdomen. The six remaining patients, who received a diagnosis of primary omental torsion or infarction based on ultrasonography and CT, underwent conservative treatment. The patients who did not undergo surgery were subsequently evaluated with imaging techniques to confirm resolution.

RESULTS

In the first three patients, symptoms were resolved by resection of the affected omental section. In the six remaining patients, a 3-6 cm mass of soft tissue in the paraumbilical region, between the rectal sheath and the transverse colon, was found. The lesions were hyperechoic or of mixed attenuation. These findings, together with the absence of other radiological and clinical signs, led to the preoperative diagnosis. Treatment was conservative and a fast recovery, observed both clinically and radiologically, was made.

CONCLUSIONS

Surgery should be avoided in selected cases of acute abdomen diagnosed as primary omental torsion.

Peritoneal carcinomatosis

The peritoneum is a mesothelial lining of the abdominal cavity (parietal) and intraperitoneal viscera (visceral). The cavity contains a small amount of fluid, which circulates from cephalad to caudal to cephalad, influenced by negative pressure under the diaphragm during exhalation, gravity, and bowel peristalsis. Peritoneal reflections and mesenteries divide the cavity into various compartments (supramesocolic, inframesocolic, and pelvis). These reflections support the peritoneal organs and provide vascular and nervous connections while within the cavity they influence pathway of intraperitoneal fluid circulation. Capillary force over convex surfaces influence stasis of fluid and promotes peritoneal seeding; thus, there are numerous areas in which peritoneal masses are seen more commonly. These areas include the undersurface of the diaphragm (negative pressure and capillary force), the omentum (bathed in fluid), the right lower quadrant (oblique course from left superior to right inferior of the small bowel mesentery), the left lower quadrant (transverse course of the sigmoid), and the pelvis (gravity). Peritoneal carcinomatosis may be either primary (mesothelioma) or metastatic. The mode of spread is by direct invasion, lymphatic permeation, peritoneal seeding or hematogenous. The imaging patterns include fibronodular stranding, nodules, plaques, and masses. Mesenteric thickening may produce pleated or stellate patterns. Spiral CT is the most useful modality in diagnosis and follow-up of peritoneal tumors.

Omental infarction in pediatric patients: sonographic and CT findings

OBJECTIVE

Children with omental infarction typically present with abdominal pain and are diagnosed clinically as having acute appendicitis. Our purpose was to perform a retrospective review of the imaging findings in nine children with omental infarction as an aid to radiologists in distinguishing this entity from acute appendicitis.

CONCLUSION

In pediatric patients with omental infarction, both CT and sonography show a heterogeneous mass characteristically situated between the anterior abdominal wall and the colon. It is important for radiologists to recognize the characteristic imaging findings seen with omental infarction.

The mechanisms of blood vessel closure in humans by the application of ultrasonic energy

BACKGROUND

The use of the ultrasonically activated scalpel (UAS) for vessel closure has attained widespread acceptance in many surgical fields. The aim of our study was to investigate the electron microscopic changes to the blood vessels after the application of UAS.

METHODS

We collected 10 arterial and 10 venous segments from vessels that had previously been closed by UAS during abdominal operations. The samples were then prepared for ultramicroscopic analysis. Pathological changes in the lumen and the three wall layers of the blood vessel were examined under scanning and transmission electron microscopy.

RESULTS

All of the vessel segments showed similar changes: the presence of a blood clot, endothelial cell condensation, coagulative necrosis of the wall, and charring of the vessel at its tip. The edge of the cut vessel were closed by the coagulation bond, which was tied up by collagen fibrils escaped from denaturation.

CONCLUSION

When ultrasonic energy is applied to tissues, it changes their structure so as to make a new extracellular matrix.

A case of incarcerated lesser sac hernia protruding simultaneously through both the gastrocolic and gastrohepatic omenta

Small bowel obstruction due to lesser sac herniation through both the gastrocolic and gastrohepatic omenta is extremely rare, and only a few reported cases have been concerned with imaging diagnosis. CT images showed distended bowel loops at the level of the cephalad part of the stomach, collapsed triangular loops and attached mesentery were depicted just behind the caudal part of the stomach. These findings provided clues to the diagnosis of this type of lesser sac hernia.

Hepatocellular carcinoma with blood supply from omental branches: treatment with transcatheter arterial embolization

PURPOSE

To evaluate the usefulness of transcatheter arterial embolization (TAE) through the omental branch in the treatment of hepatocellular carcinoma (HCC) with blood supply from the omental branch.

MATERIALS AND METHODS

Fifteen patients with HCC fed by the omental branch underwent TAE. All but one had previously undergone several therapies for HCC, including TAE. Three patients had intraperitoneal hemorrhage caused by ruptured HCC fed by the omental branch, and two necessitated emergency TAE. The technical success rate, therapeutic effect, and safety of TAE via the omental branch were evaluated.

RESULTS

Twenty-six omental branches that fed HCC were observed angiographically. Attenuation or occlusion of the hepatic artery was observed in 80%. Nineteen omental branches (73%) could be successfully embolized. Hepatic hemostasis was achieved in all patients with ruptured HCC. Tumor recurred in 80% of patients who underwent successful TAE of the omental branch, and additional therapy was performed in six patients. Ten patients died after 2-26 months (mean, 8 mo). Five patients were alive for 3-13 months (mean, 7 mo). Severe complications were not observed in any patient.

CONCLUSION

TAE of the omental branch is safe and has become technically feasible in almost all patients, but tumors frequently recur.

Radiological features of epiploic appendagitis and segmental omental infarction

Epiploic appendagitis and segmental omental infarction are more frequently encountered with the increased use of abdominal ultrasound and Computed tomography (CT) in the radiological assessment of the patient who presents clinically with acute abdominal pain. Recognition of specific imaging abnormalities enables the radiologist to make the correct diagnosis. This is important, as the appropriate management of both conditions is often conservative. Follow-up imaging features correlate with clinical improvement.

Omental infarction as a delayed complication of abdominal surgery

Omental infarction, an uncommon cause of acute abdominal pain, is the result of compromised perfusion to the greater omentum. Although its etiology remains uncertain, predisposing factors include obesity [Surg. Today 30 (2000) 451], strenuous activity [N. Z. Med. J. 111 (1998) 211], trauma, and idiopathic omental torsion. Often confused with acute appendicitis or cholecystitis on clinical grounds [Surg. Today 30 (2000) 451], its diagnosis has traditionally been one of exclusion, based on intraoperative and pathologic findings. This diagnosis can be made radiologically based on the characteristic findings of an inflammatory mass containing fat and fluid. We describe a case of right lower quadrant omental infarction temporally related to bowel surgery.

Abdominal tuberculosis affecting lesser omentum

We present a case of a young man who presented with fever and nonspecific epigastric symptoms and fluid collection in the lesser omental sac, which was proved to be of tubercular etiology.

A rare type of lesser sac hernia

We report herein the case of a female who developed a lesser sac hernia which was a rare type and was strangulated by a hole in the posterior layer of the lesser omentum. In our patient, abdominal computed tomography showed a loop of distended intestines among the liver, gallbladder and stomach. To our knowledge, there has been no previous report of transomental hernia exactly like our present case.