Biopsy interpretation of liver tumors Rish K. Pai MD, PhD Professor of Laboratory Medicine & Pathology Mayo Clinic Arizona Florida Society of Pathology Summer 2019 [email protected] ©2017 MFMER | slide-1 Liver mass biopsies: Diagnostic issues • Cirrhotics versus non-cirrhotics • Malignant tumor in the liver • How to approach these biopsies and confirm or exclude HCC • Subtypes of HCC and mixed tumors • Well-differentiated HCC • Recognize and correctly classify benign lesions • Recognize lesional tissue • Hepatocellular adenoma • Focal nodular hyperplasia ©2017 MFMER | slide-2 Liver mass biopsies: Upfront work • Have standard protocols for a biopsy of a liver mass • If multiple cores are taken, separate into different blocks • If a big core, divide and separate into two blocks • Cut unstained slides upfront to avoid wasting tissue • Don’t use up all the tissue: • Reserve tissue for molecular testing ©2017 MFMER | slide-3 Classification of liver tumors: Context! Cirrhotic liver Non-Cirrhotic liver • Hepatocellular carcinoma • < 50 y: • Hepatocellular adenoma • Cholangiocarcinoma • Focal nodular hyperplasia • Mixed • Hepatocellular carcinoma HCC/Cholangiocarcinoma • Other primary tumors • Metastases • Macroregenerative nodule (only on explant) • > 50 y: • Metastases • Dysplastic nodule (only on • Hepatocellular carcinoma explant) • Cholangiocarcinoma • Focal nodular hyperplasia • Other primary tumors ©2017 MFMER | slide-4 A note on Dysplastic nodules • Dysplastic nodule is only diagnosed in the setting of known cirrhosis – very rare to diagnose on needle biopsy (only safely diagnose on explants/resections). • Dysplastic nodule: • Foci of small cell change (increased N:C ratio) • Focal loss of reticulin • Increased arteries within the lesion ©2017 MFMER | slide-5 Screening for HCC: Imaging for pathologists • Ultrasound for cirrhotic patients every 6 months • 94% sensitivity for HCC (only 63% for early HCC) • CT or MRI is then performed to further classify and determine extent of disease • HCCs have increased arteries compared to surrounding liver: Brighter in arterial phase and darker in portal venous phase Arterial phase Equillibrium Portal venous phase ©2017 MFMER | slide-6 Cirrhotic liver: Screening for HCC • LI-RADS system (also known as OPTN classification) Adv Anat Pathol. 2015 Sep;22(5) 314-22. ©2017 MFMER | slide-7 Title • Text ©2017 MFMER | slide-8 Cirrhotic liver: HCC • Extended Toronto Criteria (for those patients beyond Milan criteria: single tumor ≤ 5cm, 2-3 tumors none >3cm, no vascular invasion and/or extrahepatic spread) • Tumor confined to liver • No radiologic evidence of biliary or venous thrombus • No cancer-related symptoms • Biopsy of the largest tumor is not poorly differentiated • Patients meeting this extended criteria did as well as those within Milan criteria ©2017 MFMER | slide-9 Grading Hepatocellular carcinoma Grade Global assessment Criteria 1 Well differentiated • Tumor cells resemble normal liver • Cytoplasm: ranges from abundant and • Hepatocellular adenoma or dysplastic eosinophilic to moderate and basophilic nodule may have to be distinguished • Nuclei: minimal to mild nuclear atypia • Reticulin: Limited reticulin loss, relatively thin plates 2 Moderately • Clearly malignant. • Cytoplasm: ranges from abundant and differentiated • Morphology still suggests hepatocellular eosinophilic to moderate and basophilic differentiation. • Nuclei: moderate nuclear atypia; occasional multinucleated tumor cells are acceptable • Reticulin: More prominent loss 3 Poorly differentiated • Clearly malignant. • Cytoplasm: ranges from moderate to scant, • Morphology is not specific for usually basophilic hepatocellular differentiation • Nuclei: marked nuclear pleomorphism, may include anaplastic giant cells • Reticulin: Variable • Macrotrabecular pattern of growth is also associated with poor prognosis ©2017 MFMER | slide-10 Case 1: • 68 year old cirrhotic male with an atypical liver mass by imaging. Masses in Cirrhotic liver: Approach • Hepatocellular? Gland forming? Both? Not sure? Histology Hepatocyte Glypican-3 Reticulin Others markers Hepatocellular Maybe (high- Maybe (high Maybe Not usually grade tumors) and low-grade (low-grade tumors) tumors) Gland forming Not usually No No Sometimes Both Yes Yes No Yes (CK7, CK19, MOC- 31) Not sure Yes Yes No Yes (CK7, CK19, others) ©2017 MFMER | slide-12 Histologic features of HCC • Abnormal architecture: thickened trabecular cords • Increased N:C ratio • Nuclear atypia (interpret with caution) • Increased arteries within the lesion • Abundant pseudoacinar structures ©2017 MFMER | slide-13 Moderately differentiated hepatocellular carcinoma Growth patterns in HCC Trabecular pattern Macrotrabecular pattern Pseudoacinar pattern Solid pattern Bile formation in a malignant tumor = HCC ©2017 MFMER | slide-16 Case 2: • 68 yo cirrhotic male with a 2.5 cm lesion with washout but no arterial enhancement. Cirrhotic background ©2017 MFMER | slide-19 Case 2: • Clearly hepatocellular • Favor neoplastic (probably HCC) • Increased N:C ratio • Pseudoacinar structures • Nuclear atypia (least useful) • Arteriolization • How to prove malignancy? ©2017 MFMER | slide-20 Markers of hepatocellular malignancy Marker HCC G1 HCC G2 HCC G3 Caveat Steatosis can distort Reticulin (loss or ++ +++ +++ reticulin, can be difficult to thickened cords) (may be focal) interpret +++ +++ +++ May be positive in CD34 (sinusoidal (sinusoidal (sinusoidal dysplastic nodules and expression) expression) expression) adenomas ++ +++ +++ Positive in some AdenoCA Glypican 3 (62%) (80%) (85%) and germ cell tumors Glutamine Diffuse GS can be seen in ++ synthetase N/A N/A some HCA, dysplastic (60%) (Diffuse) nodules, AdenoCA High background, HSP70 ++ N/A N/A occasionally dysplastic (nuclear) (60%) nodules and AdenoCA Modern Pathology (2016) 29, 283–292 ©2017 MFMER | slide-21 HSP70 Glypican-3 Glutamine synthetase CD34 Reticulin: Thickened cords, fragmentation Normal reticulin Case 2: • 68 yo cirrhotic male with a 2.5 cm lesion with washout but no arterial enhancement. • Diagnosis: Well-differentiated hepatocellular carcinoma (based on reticulin stain) ©2017 MFMER | slide-24 Mild steatosis Moderate steatosis Severe steatosis ©2017 MFMER | slide-25 Morphologic variants of HCC * Non-Cirrhotic liver * * Gastroenterol Clin North Am. 2017 Jun;46(2):365-391. ©2017 MFMER | slide-26 Steatohepatitic HCC • Occurs mainly in patients with underlying NASH • 50% of tumor must have steatohepatitic features • No affect on prognosis. Clear cell HCC • Clear cells filled with glycogen • Better prognosis ©2017 MFMER | slide-28 Cirrhotic-like HCC • Difficult to identify grossly and radiologically • HCC grows in a small nodular pattern Case 3: • 65 yo cirrhotic male with an atypical liver mass during HCC screening. ©2017 MFMER | slide-30 Cholangiocarcinoma HCC area? Solid cholangio? Masses in Cirrhotic liver: Approach • Hepatocellular? Gland forming? Both? Not sure? Histology Hepatocyte Glypican-3 Reticulin Others markers Hepatocellular Maybe (high- Maybe (high and Maybe (low- Not usually grade tumors) low-grade tumors) grade tumors) Gland forming Not usually No No Sometimes Both Yes Yes No Yes (CK7, CK19, MOC-31) Not sure Yes Yes No Yes (CK7, CK19, others) ©2017 MFMER | slide-32 Markers of Hepatocyte differentiation Marker HCC G1 HCC G2 HCC G3 Caveat +++ +++ ++ Positive in some Hep-par1 (HSA) (100%) (98%) (64%) AdenoCA +++ +++ +++ Positive in some Arginase-1 (100%) (100%) (97%) AdenoCA +++ +++ + Membranous and CD10 or pCEA (canalicular) (canalicular) (canalicular) cytoplasmic reactivity (92%) (88%) (54%) in many tumors +++ +++ + BSEP (canalicular) (canalicular) (canalicular) Not well characterized (92%) (95%) (45%) Arch Pathol Lab Med. 2015;139:1028–1034; ©2017 MFMER | slide-33 HCC versus Cholangiocarcinoma Marker HCC Cholangiocarcinoma CK7 +/- +++ CK19 +/- +++ Hep-Par1/HSA +++ - Arginase1 ++++ - pCEA or CD10 Canalicular Variable but no canalicular Glypican-3 ++ +/- MOC-31 - ++ ©2017 MFMER | slide-34 CK7: Hepatoid area CK7: Cholangio area ©2017 MFMER | slide-35 Hep-par1/HSA Arginase1 CD10 CD10: Normal liver Glypican-3: Cholangio area Glypican-3: Hepatoid area Case 3: • 65 yo cirrhotic male with an atypical liver mass during HCC screening. • Diagnosis: Combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CCA) ©2017 MFMER | slide-38 Combined HCC-cholangiocarcinoma • Combined HCC/Cholangiocarcinoma (cHCC-CCA) cHCC-CCA • Primary liver cancer with distinct HCC and CCA components • Must occurring within the same tumor nodule. • H&E based diagnosis with IHC support; no cutoff % • Higher frequency after transarterial chemoembolization • Intermediate cell carcinoma • Primary liver cancer containing intermediate cells only • H&E and IHC based diagnosis (very rare) • Other variants such as combined HCC/Cholangiocarcinoma with stem cell features and cholangiolocarcinoma are no longer recognized as distinct entities • Cholangiolocarcinoma is recognized as a subtype of intrahepatic cholangiocarcinoma Brunt et al. Hepatology. 2018 ©2017 MFMER | slide-39 Masses in Cirrhotic liver: Approach • Hepatocellular? Gland forming? Both? Not sure? Histology Hepatocyte Glypican-3 Reticulin Others markers Hepatocellular Maybe (high- Maybe (high and Maybe (low- Not usually grade tumors) low-grade grade tumors) tumors) Gland forming Not usually No No Yes (CK7 mainly) Both Yes Yes No Yes (CK7, CK19, MOC-31) Not sure Yes Yes No Yes (CK7, CK19, others) ©2017 MFMER | slide-40 Malignant masses in Non-cirrhotic liver • Hepatoid/heptocellular? Gland forming? Can’t tell?