Diagnostic Approach to Septated Liver Cysts

Introduction to Septated Liver Cysts

A septated liver cyst requires MRI characterization to distinguish between benign entities and mucinous cystic neoplasm (MCN), which mandates surgical resection when worrisome features are present 1

The American Association for the Study of Liver Diseases recommends that hemorrhagic simple cysts be distinguished from MCNs based on the presence of heterogeneous hyperintense signal on both T1- and T2-weighted sequences, with fluid-fluid levels representing blood-filled lakes between septa 2, 3
The European Association for the Study of the Liver states that polycystic liver disease (PLD) is defined as >10 hepatic cysts, which may have septations from prior hemorrhage or infection 4
The American College of Radiology recommends that Caroli disease be characterized by segmental intrahepatic saccular or fusiform cystic dilatations of bile ducts, with a pathognomonic "central dot sign" representing fibrovascular bundles within dilated ducts 4, 2

The American College of Surgeons recommends that mucinous cystic neoplasm (MCN) be suspected in middle-aged women with septated cysts, particularly when worrisome features such as thick septations, mural nodularity, and internal hemorrhage are present 1, 5
The National Comprehensive Cancer Network states that MCNs carry a 3-6% risk of invasive carcinoma, and that surgical resection is recommended when ≥1 major feature (thick septations, mural nodularity) PLUS ≥1 minor feature (upstream biliary dilatation, thin septations, internal hemorrhage, perfusional changes, or <3 coexistent hepatic cysts) are present 1, 5

The American College of Radiology recommends that MRI be used as the primary modality for characterizing septated cysts, due to its superior ability to assess cyst contents and differentiate benign from malignant septations 4, 2, 1
The Society of Abdominal Radiology states that contrast-enhanced ultrasound can be used to identify vascularized septations, which are present in malignancy but absent in benign lesions 2

The American College of Radiology warns against mistaking hemorrhagic septations for malignancy, and recommends that true MCNs be distinguished from hemorrhagic simple cysts based on the presence of thick septations and nodularity 1, 3
The European Association for the Study of the Liver recommends against using CT as the primary modality for diagnosing septated cysts, due to its limited ability to assess cyst contents and differentiate benign from malignant septations 4, 2, 3

The American Association for the Study of Liver Diseases recommends obtaining MRI as the first-line imaging modality for any septated liver cyst, as it provides 94-98% specificity for mucinous cystic neoplasm (MCN) diagnosis when multiple worrisome features are present, in patients with suspected liver cysts 6
MRI is superior to CT for characterizing cyst contents, particularly in differentiating benign from malignant septations, in the diagnostic workup of septated liver cysts 6

The presence of thick septations (>2mm) is a major worrisome feature that requires careful evaluation, as it has a high association with MCN, in patients with septated liver cysts 6
Mural nodularity or solid components are major worrisome features that require careful evaluation, as they are highly suggestive of MCN, in the diagnostic workup of septated liver cysts 6
Wall enhancement on contrast imaging is a major worrisome feature that requires careful evaluation, as it is highly suggestive of MCN, in patients with septated liver cysts 6
Internal hemorrhage is a minor worrisome feature that requires careful evaluation, as it can be associated with MCN, in the diagnostic workup of septated liver cysts 6

The American College of Surgeons recommends proceeding directly to complete surgical resection if ≥1 major feature + ≥1 minor feature are present, as this combination carries 94-98% specificity for MCN, which has a 3-6% risk of invasive carcinoma and high recurrence rates (0-26%) after incomplete resection, in patients with septated liver cysts 6
Complete excision is the gold standard for the treatment of MCN, as fenestration alone is associated with higher tumor recurrence rates, in patients with septated liver cysts 6
Enucleation with free margins is an acceptable treatment option for centrally located tumors, in patients with septated liver cysts 6
Major liver resections, including extended hemihepatectomy, may be necessary for complete removal of the cyst, in patients with septated liver cysts 6