| Omental cake | |
|---|---|
| Other names | omental thickening |
 | |
| Axial abdominal computed tomography featuring omental caking due to peritoneal carcinomatosis | |
| Causes | metastatic cancer, infectious disease |
| Diagnostic method | medical imaging |
Omental cake is a radiologic sign indicative of an abnormally thickened greater omentum. [1] It refers to infiltration of the normal omental structure by other types of soft-tissue or chronic inflammation resulting in a thickened, or cake-like appearance. [2]
Typically, it is caused by infiltration of metastatic tumors arising from the stomach, ovary, or colon. This dissemination of cancerous cells that do not originate from the omentum itself is called peritoneal carcinomatosis. It can occur other regional tumors such as lymphoma where it is associated with regional lymphadenopathy. [3] It can also rarely occur as a result of infectious causes such as tuberculous peritonitis, peritoneal coccidioidomycosis, and histoplasmosis. [4]
For the most common cause, peritoneal carcinomatosis, omental caking is associated with a wide variety of symptoms. Ascites and intestinal peristalsis is known to have an effect on how diffusely the cancer cells are spread throughout the abdomen. This wide range of presentation makes omental caking difficult to diagnose based on symptoms alone. [5]
In patients with omental caking due to peritoneal lymphomatosis secondary to cancers such as Non-Hodgkin's lymphoma or MALT lymphoma, the most frequent symptoms encountered are abdominal pain, gastric distention, and weight loss. [6]
Causes such as bacterial and fungal infections are associated with diffuse abdominal pain, intraperitoneal fluid accumulation, weight loss, fevers, and night sweats. The most common radiographic feature among patients with suspected tuberculous peritonitis was septated compartments of ascitic fluid on ultrasound and abnormal chest X-ray suggestive of previous tuberculosis. [7]
Due to the variety of symptoms experienced by patients with omental caking, [5] omental cakes are most frequently discovered on abdominal computed tomography (CT) or ultrasound. Plain film radiography (X-ray) is not a suggested modality for investigating the spread of cancerous cells in the abdomen due to the poor spatial resolution amongst soft-tissue densities. Contrast resolution obtained through CT allows radiologists to investigate omental caking for morphology, intraperitoneal fluid, and regional lymphadenopathy assists in proper diagnosis so clinicians, surgeons, and oncologists can plan the appropriate course of treatment. [8]
After omental cakes have been identified on CT or ultrasound, it may be appropriate to gain more information on the characteristics of the disease by undergoing nuclear medicine scans that can identify tissues where the cancerous cells may have spread [9] or magnetic resonance imaging (MRI) for a higher degree of spatial resolution. [10] Suspected infectious etiologies may require another degree of medical testing including blood antigen or antibody analysis. [11] Yet, in both malignant and infectious cases, image-guided biopsy with pathologic correlation is the most definitive way to confirm the diagnosis. [10]
The presence of omental cakes have long been seen as an indication of poor prognosis in patients with advanced-stage ovarian or gastrointestinal cancer, and medical teams usually address this through more advanced and aggressive treatments such as cytoreductive surgery and hyperthermic-intraperitoneal chemotherapy (HIPEC). [12] During surgery, the presence of omental caking makes incomplete resection more likely. [13] In patients where omental spread is completely removed, intestinal resections are more likely to be encountered due to the caked omentum's propensity for spreading malignancy to adjacent organs. [13] [14] If malignant, as patients undergo treatment they are likely to undergo routine nuclear medicine imaging as surveillance for response to the treatment or recurrence of disease. [15]
Common disease presentations that are different but may appear similar include pseudomyxoma peritonei, peritoneal mesothelioma, splenosis in patients with a history of splenectomy, and diffuse peritoneal leiomyomatosis. [16] These diagnoses should be considered in patients with suspected omental caking and a history that makes malignant or infectious causes less likely. Image-guided biopsy with pathologic correlation is the gold-standard method for distinguishing these entities. [10]
Omental cakes have long been described during malignancy-related surgical interventions. In 1985, Drs. Stephen Rubesin and Marc Levine were the first to publish a radiographic review of omental caking and to describe the propensity for omental spread to facilitate colonic metastases due to the proximity of the greater omentum to bowel. [14] Since then, many radiologists have adopted techniques to investigate omental thickening and irregularities in density using the Hounsfield scale and other radiographic tools to determine the extent of abdominal disease. [4]
The peritoneum is the serous membrane forming the lining of the abdominal cavity or coelom in amniotes and some invertebrates, such as annelids. It covers most of the intra-abdominal organs, and is composed of a layer of mesothelium supported by a thin layer of connective tissue. This peritoneal lining of the cavity supports many of the abdominal organs and serves as a conduit for their blood vessels, lymphatic vessels, and nerves.
Appendicitis is inflammation of the appendix. Symptoms commonly include right lower abdominal pain, nausea, vomiting, and decreased appetite. However, approximately 40% of people do not have these typical symptoms. Severe complications of a ruptured appendix include widespread, painful inflammation of the inner lining of the abdominal wall and sepsis.
Peritonitis is inflammation of the localized or generalized peritoneum, the lining of the inner wall of the abdomen and cover of the abdominal organs. Symptoms may include severe pain, swelling of the abdomen, fever, or weight loss. One part or the entire abdomen may be tender. Complications may include shock and acute respiratory distress syndrome.
Bowel obstruction, also known as intestinal obstruction, is a mechanical or functional obstruction of the intestines which prevents the normal movement of the products of digestion. Either the small bowel or large bowel may be affected. Signs and symptoms include abdominal pain, vomiting, bloating and not passing gas. Mechanical obstruction is the cause of about 5 to 15% of cases of severe abdominal pain of sudden onset requiring admission to hospital.
Interventional radiology (IR) is a medical specialty that performs various minimally-invasive procedures using medical imaging guidance, such as x-ray fluoroscopy, computed tomography, magnetic resonance imaging, or ultrasound. IR performs both diagnostic and therapeutic procedures through very small incisions or body orifices. Diagnostic IR procedures are those intended to help make a diagnosis or guide further medical treatment, and include image-guided biopsy of a tumor or injection of an imaging contrast agent into a hollow structure, such as a blood vessel or a duct. By contrast, therapeutic IR procedures provide direct treatment—they include catheter-based medicine delivery, medical device placement, and angioplasty of narrowed structures.
In human anatomy, the mesentery, an organ that attaches the intestines to the posterior abdominal wall, comprises the double fold of the peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines.
The peritoneal cavity is a potential space located between the two layers of the peritoneum—the parietal peritoneum, the serous membrane that lines the abdominal wall, and visceral peritoneum, which surrounds the internal organs. While situated within the abdominal cavity, the term peritoneal cavity specifically refers to the potential space enclosed by these peritoneal membranes. The cavity contains a thin layer of lubricating serous fluid that enables the organs to move smoothly against each other, facilitating the movement and expansion of internal organs during digestion.
A chest radiograph, chest X-ray (CXR), or chest film is a projection radiograph of the chest used to diagnose conditions affecting the chest, its contents, and nearby structures. Chest radiographs are the most common film taken in medicine.
Pseudomyxoma peritonei (PMP) is a clinical condition caused by cancerous cells that produce abundant mucin or gelatinous ascites. The tumors cause fibrosis of tissues and impede digestion or organ function, and if left untreated, the tumors and mucin they produce will fill the abdominal cavity. This will result in compression of organs and will destroy the function of the colon, small intestine, stomach, or other organs.
Pyonephrosis is a dangerous kidney infection that is characterized by pus accumulation in the renal collecting system. It is linked to renal collecting system blockage and suppurative renal parenchymal destruction, which result in complete or nearly complete kidney failure.
The greater omentum is a large apron-like fold of visceral peritoneum that hangs down from the stomach. It extends from the greater curvature of the stomach, passing in front of the small intestines and doubles back to ascend to the transverse colon before reaching to the posterior abdominal wall. The greater omentum is larger than the lesser omentum, which hangs down from the liver to the lesser curvature. The common anatomical term "epiploic" derives from "epiploon", from the Greek epipleein, meaning to float or sail on, since the greater omentum appears to float on the surface of the intestines. It is the first structure observed when the abdominal cavity is opened anteriorly.
Epiploic appendagitis (EA) is an uncommon, benign, self-limiting inflammatory process of the epiploic appendices. Other, older terms for the process include appendicitis epiploica and appendagitis, but these terms are used less now in order to avoid confusion with acute appendicitis.
Carcinosis, or carcinomatosis, is disseminated cancer, forms of metastasis, whether used generally or in specific patterns of spread.
Leptomeningeal cancer is a rare complication of cancer in which the disease spreads from the original tumor site to the meninges surrounding the brain and spinal cord. This leads to an inflammatory response, hence the alternative names neoplastic meningitis (NM), malignant meningitis, or carcinomatous meningitis. The term leptomeningeal describes the thin meninges, the arachnoid and the pia mater, between which the cerebrospinal fluid is located. The disorder was originally reported by Eberth in 1870. It is also known as leptomeningeal carcinomatosis, leptomeningeal disease (LMD), leptomeningeal metastasis, meningeal metastasis and meningeal carcinomatosis.
Peritoneal mesothelioma is the name given to the cancer that attacks the lining of the abdomen. This type of cancer affects the lining that protects the contents of the abdomen and which also provides a lubricating fluid to enable the organs to move and work properly.
Hyperthermic intraperitoneal chemotherapy (HIPEC) is a type of hyperthermia therapy used in combination with surgery in the treatment of advanced abdominal cancers. In this procedure, warmed anti-cancer medications are infused and circulated in the peritoneal cavity (abdomen) for a short period of time. The chemotherapeutic agents generally infused during IPHC are mitomycin-C and cisplatin.
Omental infarction, or omental torsion, is an acute vascular disorder which compromises tissue of the greater omentum—the largest peritoneal fold in the abdomen.
Peritoneal carcinomatosis (PC) is intraperitoneal dissemination (carcinosis) of any form of cancer that does not originate from the peritoneum itself. PC is most commonly seen in abdominopelvic malignancies. Computed tomography (CT) is particularly important for detailed preoperative assessment and evaluation of the radiological Peritoneal Cancer Index (PCI).
Encapsulating peritoneal sclerosis(EPS) is a chronic clinical syndrome with an insidious onset that manifests as chronic undernourishment accompanied by sporadic, acute, or subacute gastrointestinal obstruction symptoms. Peritoneal dialysis is most commonly linked to encapsulating peritoneal sclerosis, especially when peritoneal dialysis is stopped. The diagnosis is verified by macroscopic and/or radiological observations of intestinal encapsulation, calcification, thickening of the peritoneum, or sclerosis.
Afferent loop syndrome is an uncommon side effect of gastric surgery. The afferent loop is made up of a segment of duodenum and/or proximal jejunum located upstream of a double-barrel gastrojejunostomy anastomosis. Abdominal pain and distension are signs of increased intraluminal pressure resulting from the accumulation of enteric secretions in the obstructed afferent loop.