Focal Fat Infarction of the Falciform Ligament: Typical CT Appearance of a Rare Form of Intra-peritoneal Focal Fatty Infarction

Falciform Ligament Infarction: A Case Report and Review of the Literature

The falciform ligament is a double peritoneal fold that separates the left and right hepatic lobes anatomically. Fatty-falciform ligament appendage torsion (F-FLAT) is defined as torsion of the extraperitoneal fat within the falciform ligament causing fat infarction, which is an uncommon surgical presentation, scarcely documented within the current literature. The objective of presenting this case report and reviewing the literature on F-FLAT is to discuss the clinical presentation, possible associated factors and management strategies in regard to this rare pathology. A 72-year-old female patient presented to the emergency department with a seven-day history of epigastric pain, reduced appetite and nausea. On admission, the patient was stable and apyrexial with abdominal examination highlighting she was tender in her right upper quadrant and epigastric region. Due to the patient's unremitting abdominal pain despite appropriate analgesia, CT of the abdomen and pelvis (CTAP) with intravenous contrast was done and a diagnosis of F-FLAT was made. The patient was treated with antibiotics and analgesia, had a negative abdominal ultrasound (US) result and due to her symptoms settling by the second day of admission, she was discharged the same afternoon. A literature review into falciform ligament infarction was conducted by two independent reviewers across four different databases: PubMed, Medline, Embase and the Cochrane Library. Search terms included "falciform ligament" OR "falciform" AND "infarction" (likewise with Medical Subject Headings, or MeSH, terms in the Cochrane Library). Eligibility criteria and our subsequent inclusion criteria were based on studies specifically discussing falciform ligament infarction and published in English. Study types were by majority case reports, but also included one literature review and a book source as well as two pictorial radiological reviews. All 13 patients presented with abdominal pain, but only 53% presented with raised infective/inflammatory markers. The majority of patients had abdominal US as a first-line investigation with 9 of 13 patients also having a CTAP with contrast, which classically showed fat stranding in the falciform ligament. Two patients had no evidence of any radiological investigation. Initially all cases were managed conservatively with non-steroidal anti-inflammatory drugs and analgesia, but in 62% of the cases (8/13), surgical intervention was needed due to unresolving abdominal pain. All eight of the excised falciform ligaments showed evidence of infarction and necrosis histologically. In conclusion, F-FLAT is a relatively rare condition making it difficult to build higher level evidence studies. The current literature has revealed some evidence of incomplete and inconsistent data, for example, in the biochemical results and management techniques presented, yet contrast-enhanced CT seems moderately sensitive for detection in the reviewed literature. Though F-FLAT is rare and unfamiliar, it is vital we exclude common acute surgical pathologies that F-FLAT mimics and monitor for unsettling symptoms that could change the management trajectory.

Not Just Fat: Imaging in Abdominal Fat Pathology

Fat in abdomen has diverse distribution and function. Insult to fat due to several causes can result in infarction or necrosis and present as acute abdomen clinically. Intra-abdominal focal fat infarction is one such condition that comprises of epiploic appendagitis, perigastric appendagitis, omental infarction, and torsion of fatty appendage of falciform ligament that have characteristic imaging features. Secondary causes of fat necrosis include pancreatitis or trauma related. Metabolic or responsive fat changes, like hypertrophy and dystrophy, can be diagnosed on imaging especially on computed tomography. Mesentric fat stranding including the mesentric panniculitis spectrum poses diagnostic dilemma and the causes and imaging role are covered in this review. Some infections and neoplasms that preferably affect abdominal fat compartments may mimic benign conditions, although some have specific patterns of involvement.

Clinics in diagnostic imaging (203). Focal infarction of the falciform ligament fatty appendage

A 56-year-old man presented to the emergency department with acute upper abdominal pain and mild leucocytosis. The pain was not relieved by intravenous analgesia. Computed tomography of the abdomen and pelvis demonstrated a focal area of fat stranding with a thin peripheral rim of high attenuation and a punctate central hyperdense dot in the vicinity of the falciform ligament. The diagnosis of focal infarction of the falciform ligament fatty appendage was made based on the imaging findings. The patient responded well to conservative management and was discharged for outpatient follow-up. Focal infarction of the falciform ligament fatty appendage is extremely rare and can mimic various causes of acute abdomen that require emergency surgery. Hence, correct radiological diagnosis is essential to avoid unnecessary surgical intervention. We herein discuss the similarities and differences with other common companion cases such as epiploic appendagitis and omental infarction.