Brief history:
Patient, female, 42 years;
Main complaints: Diarrhea for more than 2 years, worsening with right lower quadrant pain for 5 days. Laboratory tests have low white blood cell counts.
Ultrasound: 6.2*2.7 cm uneven echo area is seen in the right lower quadrant.
Pathology: A piece of gray-yellow fatty tissue, 6 *4.5 *1.3 cm, nodular sensation in some areas, dark red toughness, range 4 *2 cm, no obvious nodules.
Diagnosis and recommendations: (large omentum) sent to the omental tissue for bleeding, necrosis, chronic inflammatory cell infiltration and fibrous tissue hyperplasia.
Large omental infarction
Due to the abundance of collateral circulation of the large omentum, large omental infarction is rare.
Primary large omental infarction is often a hemorrhagic infarction caused by blood supply disorders, the lower right part of the large omentum is relatively prone to infarction, and it is currently believed that its pathological and anatomical basis is that the free margin on the right side of the large omentum has less blood supply and collateral circulation than other parts, and the right edge of the large omentum is prone to venous tortuous, in addition, the large omentum can reach deep into the anterior pelvic cavity, and the large omental infarction can also occur here.
Secondary large omental infarction may occur after omental surgical trauma or inflammation, usually near the surgical site rather than in the typical lower right part of primary large omental infarction.
Onset of large omental infarction is mild, occurring in about 15% of children. Clinical manifestations are mainly fixed abdominal pain that lasts for several days (subacute episodes), patients can accurately indicate the location of abdominal pain, pain can be very severe, but the systemic reaction is not serious, rarely appear gastrointestinal symptoms such as nausea, vomiting, and diarrhea, and the white blood cell count is normal or mildly elevated. It is easily misdiagnosed as appendicitis, ileophylitis, diverticulitis and cholecystitis.
In most cases, the disease needs to be diagnosed by a radiologist after imaging, and CT is the primary imaging test for the disease. CT is usually a single large (more than >5 cm in diameter) fat density mass, often without a continuous high-density ring, the typical site is close to the ascending colon and the cecum but not touching, there may be fat cords around, and there are many abnormal changes in the adjacent colon, and occasional thickening is seen.
Large omental infarction. The range is large, and the high density ring is discontinuous.
Differential diagnosis - other celiac inflammatory fatty masses
Primary lipoplasticitis
Intestinal diploid is a number of protrusions of varying sizes and morphologies formed by the local aggregation of subserous fat near the colonic belt, most common in the left half of the colon and the cecum. Lipoplastic inflex is a self-limiting disease. May occur at any age, with a peak age of 40 years. Clinical presentation is similar to that of large omental infarction.
CT features: a circular fat density mass adjacent to the intestinal tube on the contralateral side of the mesenteric membrane ("ring sign"), with a cord-like hyper-density shadow visible in the surrounding fat gap, seen in all cases. The center of the lesion is punctuated and linear, high-density shadow, representing a venous thrombosis, and the incidence is about 42.9%. The adjacent intestinal wall of the lesion may be thickened, but less commonly, there is no significant effusion around the intestinal canal.
Female, 56 years old, left lower quadrant pain. CT shows a paracolonal paracolonoid fat density mass shadow with an annular high density at the edges, a punctate high density shadow in the center, a cloud flocculent density increased shadow around the lesion, and a thickened adjacent peritoneum.
Female, 48 years old, left lower quadrant pain. CT shows an oval fat density lesion at the beginning of the sigmoid colon, a high-density ring at the edge, a quasi-circular high-density in the center, a cord-like oozing shadow around the lesion, and a thickening of the peritoneum of the adjacent parietic layer.
Male, 32 years old, left lower quadrant pain. CT shows an oval fat density lesion on the medial anterior medial sigmoid colon, with an annular hyperglud at the margins, a cord-like oozing shadow around it, and a thickening of the adjacent peritoneum. Enhanced scans show lesion margin strengthening.
Diverticulitis of the colon
The most common complication of the diverticulum is generally considered to be due to weakened diverticular contractility or occlusion of the diverticular orifice, mucus secretion and bacterial growth, and the production of toxins to produce inflammation, similar to the occurrence of appendicitis. Because the walls of the colonic diverticulum are often missing muscle layers, inflammation spreads easily. Colonic diverticulitis is older, the clinical abdominal pain is widespread, nausea, vomiting, fever and other symptoms may appear, and the white blood cell count is increased.
CT signs: complicated infection of the colonic diverticulum is a sac-like structure protruding outward from the intestinal wall, which may be filled with gas, liquid, or fecal stones, exudation of the surrounding fat space, thickening of the adjacent colon wall, and thickening of the adjacent fascia. Diverticulitis can be complicated by perforation, bleeding, and pericolonal abscesses, or it can form fistulas, intestinal obstruction, and portal phlebitis with surrounding structures. Diverticulitis bleeding is characterized by high-density shadows in the intestinal lumen and diverticulum, which are less dense than fecal stones, and the morphology and number of high-density shadows are changed in CT review. Bubbles around the diverticulum and free gases in the abdominal cavity suggest concurrency perforation.
Ascending colonic diverticulitis and diverticulitis
Rises colonic diverticulitis and perforation
Sclerosing mesenteritis
For chronic nonspecific inflammation involving mesenteric adipose tissue, the cause may be related to an autoimmune response. The average age is about 50, and it is more common in men. Clinically, there may be abdominal pain, fever, nausea, vomiting, etc. Most are self-limiting and have a good prognosis. Pathologies include mesenteric lipotenstrophy (predominantly fat necrosis), mesenteric aliphatic inflammatory disease (chronic inflammation predominates), and flinchable mesenteritis (fibrosis predominates).
CT features: CT manifestations vary according to different pathological processes, ranging from mild mesenteric fat density to soft tissue masses, and difficulty distinguishing from tumors when soft tissue shadow is dominant. The mesenteric blood vessels are not replaced and form a "fat ring" around the surrounding fat. Lesions are often larger, occurring mostly at the root of the small mesenteric membrane, occasionally affecting the mesenteric membrane, and rarely in areas around the pancreas, large omentum, and retroperitoneum.
Mesenteric lipomaitis. Female, 49 years old. Pain in the epigastric region and discomfort in the present. The lesion is large in scope and the internal vascular deformation is normal.
Sclerosing mesenteritis, ct enhancement showing lesions with a predominant soft-tissue shadow, and a "fat ring" (arrow) sign (arrow) visible around the mesenteric vessels.
The main points of identification
Case review
Lesions close to ascending colon + abdominal pain presentation + low white blood cell count + large fat density (6 cm in diameter) + high density ring discontinuities – large omental infarction.
Source: Image Time
【Copyright Notice】This platform is a public welfare learning platform, reprinted for the purpose of transmitting more learning information, and has indicated the author and source, such as teachers who do not want to be disseminated can contact us to delete