Liver, Intrahepatic Mass: Diagnosis and Margins



Liver, Intrahepatic Mass: Diagnosis and Margins










Oligometastatic colon carcinoma or neuroendocrine tumors to the liver may undergo resection. Surgeons often request intraoperative evaluation of the hepatic margin to ensure complete resection.






Metastatic colon carcinoma is usually easily recognized by columnar cells and dirty necrosis. If the lesion is a small nodule on the liver capsule, bile duct adenoma or hamartoma should be considered.


SURGICAL/CLINICAL CONSIDERATIONS


Goal of Consultation



  • Determine whether liver mass is benign or malignant


  • Evaluation of margins


Change in Patient Management



  • If lesion is benign, wide margin of resection is unnecessary


  • If lesion is present at margin, additional tissue is removed, if surgically feasible


Clinical Setting



  • Liver lesions will usually have been diagnosed by core needle biopsy or fine-needle aspiration prior to surgery



    • Open biopsy may be preferred in some cases due to concern for needle-track seeding


  • Patients may benefit from resection of



    • Hepatocellular adenoma


    • Focal nodular hyperplasia, increasing in size or multiple


    • Hepatocellular carcinoma


    • Intrahepatic cholangiocarcinoma


    • Oligometastatic carcinoma to liver (colon cancer most common primary site)


    • Metastatic neuroendocrine tumors


  • Malignant lesions are resected with a margin of at least 1 cm, if possible


  • Superficial or capsular liver mass may be detected during operation for another reason



    • Surgeon may request intraoperative evaluation to guide surgery and for staging


SPECIMEN EVALUATION


Gross



  • Measure specimen in 3 dimensions


  • Cut parenchymal portion of liver is identified



    • Evaluate surface for any areas grossly suspicious for tumor involvement


  • Ink margin



    • Liver capsule is not a margin and should not be inked


    • Be wary of ink leaking into cracks in tissue


  • Thinly slice specimen perpendicular to margin



    • Identify all mass lesions


    • Number of metastatic foci found in resection has clinical and prognostic relevance



      • Correlation with number of lesions seen on imaging is necessary to ensure surgeon removed all foci of tumor


      • Slices must be 4-5 mm thick to detect small metastatic foci


  • Measure closest distance to margin


  • Only a fibrotic tumor bed may be visible in posttreatment resections


Frozen Section



  • If there is a grossly suspicious area for margin involvement, perpendicular frozen section should be evaluated


MOST COMMON DIAGNOSES


Metastatic Carcinoma



  • Most common diagnosis (˜ 25% of total, ˜ 75% of malignant diagnoses)


  • Multiple hard white masses



    • Often with central necrosis


  • Oligometastatic colonic carcinoma may be resected


  • Margin should be free of carcinoma but wide margin is not required


Hepatocellular Carcinoma



  • 2nd most common diagnosis (˜ 25% of malignant diagnoses)


  • May present as a solitary mass, dominant mass with satellite nodules, or rarely, in diffusely infiltrative pattern



    • Variegated yellow-white appearance with necrosis and hemorrhage in larger lesions


  • Surrounding liver is usually cirrhotic




    • Nodule within a nodule may be an area of carcinoma with a dominant nodule or carcinoma arising in a dysplastic nodule


  • Tumor cells closely resemble normal hepatocytes when well differentiated



    • Large polygonal cells with large nucleus, prominent nucleolus, and abundant cytoplasm


    • Cytoplasmic bile may be present and support origin in liver


    • Thickened trabeculae with > 2 cells


    • Absent portal tracts


  • Poorly differentiated carcinomas are more easily recognized as malignant, but distinction of hepatocellular from cholangiocarcinoma may be difficult


  • Fibrolamellar carcinoma



    • Forms large (typically > 10 cm), circumscribed, hard brown mass


    • Surrounding liver is typically noncirrhotic


Cholangiocarcinoma



  • Most cancers are advanced at time of diagnosis


  • Large, gray-white, hard, irregular masses


  • Cholangiocarcinoma cannot be distinguished from metastatic adenocarcinoma on frozen section


  • Intrahepatic duct and bile duct margins should be evaluated for dysplasia and malignancy


Pediatric Tumors



  • Rare



    • Tissue for ancillary studies should be considered (electron microscopy, cytogenetic studies, snap frozen for molecular studies)


  • Some tumors that occur in adults also occur in children



    • Hepatocellular carcinoma


    • Focal nodular hyperplasia


    • Hepatocellular adenoma


  • Carcinomas may have undergone neoadjuvant therapy with chemotherapy &/or radiation


  • Hepatoblastoma



    • Large circumscribed mass with variegated appearance including cysts, necrosis, and hemorrhage


  • Mesenchymal hamartoma



    • Large circumscribed mass with multiple cystic spaces filled with fluid



      • Solid areas may fibrotic, myxoid, with entrapped foci of normal liver


  • Embryonal (undifferentiated) sarcoma



    • Usually occurs between ages of 6 and 11


    • Circumscribed soft tumor with solid and cystic appearance



      • Hemorrhage and necrosis may be present


Bile Duct Adenoma/Hamartoma

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Jul 7, 2016 | Posted by in PATHOLOGY & LABORATORY MEDICINE | Comments Off on Liver, Intrahepatic Mass: Diagnosis and Margins

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