E1403. Uncommon Liver Lesions: Beyond “The Common Five”
  1. Rangarajan Purushothaman; University of Arkansas for Medical Sciences
  2. Gitanjali Bajaj; University of Arkansas for Medical Sciences
  3. George Vilanilam; University of Arkansas for Medical Sciences
  4. Roopa Ram; University of Arkansas for Medical Sciences
  5. Tarun Pandey; University of Arkansas for Medical Sciences
  6. Kedar Jambhekar; University of Arkansas for Medical Sciences
Imaging characteristics of common liver lesions such as metastasis, cholangiocarcinoma and hepatocellular carcinoma are well described, but there is a paucity of literature of uncommon liver lesions. Some of these uncommon liver lesions have characteristic imaging findings. Prompt diagnosis of these lesions through imaging helps in appropriate management and avoid further diagnostic tests, such as biopsies and unnecessary follow ups.

Educational Goals / Teaching Points
The incidence of liver tumors has increased fourfold over the last three decades. With advances in imaging, there is an increased detection of primary liver tumors, some of them being symptomatic and the rest detected incidentally. The common primary liver lesions include – hepatocellular carcinoma, hepatic adenoma, focal nodular hyperplasia and cholangiocarcinoma. Literature about imaging features of uncommon liver tumors is sparse. Computed Tomogram (CT) and Magnetic Resonance Imaging (MRI) are excellent tools that aid in detection and characterization of liver lesions. The educational goals are to learn the incidence and pathological classification of various primary hepatic tumors. To describe the incidence, clinical features of various uncommon primary hepatic tumors for e.g. epithelioid hemangioendothelioma, hepatic mucinous neoplasm, hydatid cyst, solitary fibrous tumor, inflammatory pseudo tumor, lymphoma, biliary cyst adenoma, combined HCC-Cholangiocarcinoma etc. To learn the essential role of imaging features in diagnostic algorithms such as indications for percutaneous biopsy and various treatment modalities. To gain knowledge regarding follow-up recommendations of uncommon primary liver tumors.

Key Anatomic/Physiologic Issues and Imaging Findings/Techniques
Primary liver malignancies can be divided by their cell of origin. The broad categories include: Hepatic, Biliary, Vascular, Mesenchymal and other Infectious/Inflammatory etiologies. Each of these categories has benign and malignant lesions. These lesions may have characteristic Ultrasound (US), CT or MRI findings.

It is important for radiologists to be aware of the imaging findings of uncommon liver tumors. This helps in further management and avoids the need for unnecessary biopsies and follow-up imaging.