Biopsy Interpretation of Liver Tumors

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]

• 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

• 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

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

• 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

• 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

• LI-RADS system (also known as OPTN classification)

• Text

• 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

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

• 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)

• Abnormal architecture: thickened trabecular cords • Increased N:C ratio • Nuclear atypia (interpret with caution) • Increased arteries within the lesion • Abundant pseudoacinar structures

Pseudoacinar pattern Solid pattern Bile formation in a malignant tumor = HCC

• 68 yo cirrhotic male with a 2.5 cm lesion with washout but no arterial enhancement.

Cirrhotic background

• Clearly hepatocellular • Favor neoplastic (probably HCC) • Increased N:C ratio • Pseudoacinar structures • Nuclear atypia (least useful) • Arteriolization • How to prove 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

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)

* Non-Cirrhotic liver

Gastroenterol Clin North Am. 2017 Jun;46(2):365-391.

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.

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)

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;

Marker HCC Cholangiocarcinoma

CK7 +/- +++

CK19 +/- +++

Hep-Par1/HSA +++ -

Arginase1 ++++ -

pCEA or CD10 Canalicular Variable but no canalicular

Glypican-3 ++ +/-

MOC-31 - ++

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)

• 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)

• Hepatoid/heptocellular? Gland forming? Can’t tell? Histology Hepatocyte Glypican-3 Cytokeratins Other markers markers

Hepatoid/hepatocellular Yes Yes (interpret Maybe No (but depends with caution) on history)

Gland forming No No Yes (CK7, CK20) Yes: Usually CDX2, SATB2, TTF1 (others depend on history) Can’t tell Yes Maybe Yes (Cam5.2, Not yet, unstained CK7, others) slides, do IHC in phases

• 53 yo female with a liver mass. Liver is non-cirrhotic

• Hepatoid/hepatocellular? Gland forming? Can’t tell? Histology Hepatocyte Glypican-3 Cytokeratins Other markers markers

Hepatoid/ Yes Yes (interpret Maybe No (but depends on hepatocellular with caution) history)

Gland forming No No Yes (CK7, CK20) Yes: Usually CDX2, SATB2, TTF1 (others depend on history)

Can’t tell Yes Maybe Yes (Cam5.2, CK7, Not yet, unstained others) slides, do IHC in phases

Glypican-3 Arginase-1

• Cholangiocarcinoma?

• Metastatic hepatoid carcinoma?

• Combined HCC-cholangiocarcinoma?

• Variant of hepatocellular carcinoma?

Mod Pathol. 2013 Jun;26(6):782-91.

CK7 CD68 Case 5: 40 yo female with a liver mass

Normal liver

Abnormal Features • Sinusoidal dilatation • Portal tract-like structures with inflammation, multiple arteries and rare bile ductules (no true bile ducts) • No fibrous bands or larger arteries Reticulin: Normal trabecular thickness

Differential Fibrous Isolated Bile Trabecular bands with “naked” ductules thickness large small arteries arteries Well- Not usually Yes No Abnormal differentiated Hepatocellular carcinoma Hepatocellular No Yes Sometimes Normal adenoma

Focal nodular Yes Rarely Yes Normal hyperplasia

• Increasing incidence since widespread use of oral contraceptives • Other risk factors: anabolic steroids, glycogen storage disease, FAP, MODY3 • F>>>M • Low-risk of malignant transformation • Symptoms: pain, bleed, infarct, rupture • Treatment: Avoid OCP and pregnancy; surgery

©2017 MFMER | slide-52 Hepatocellular adenomas (HCA) • Morphologic and molecular subtypes • HNF1a mutated HCA • Biallelic mutations in HNF1A (90% somatic, 10% germline) • Inflammatory HCA • Constitutive activation of Stat3 due to mutations in pro-inflammatory pathways • May also develop CTNNB1 mutations and progress to HCC • b-catenin mutated HCA • 3 different mutation types occur in CTNNB1 (weakly active, mod active, and highly active) • High risk of malignant transformation to HCC • HCA-unclassified

Unclassified HCA β-catenin mutated HCA ~15% β-catenin mutated Inflammatory HCA ~10% HNF1α ~35% mutated HCA

~40% Inflammatory HCA

Subtype Histologic features LFABP CRP/SAA Glutamine β-catenin Synthetase H-HCA • Steatosis Loss Patchy Perivenular Membranous IHCA • Inflamed portal-tract Retained Diffusely Perivenular Membranous like structures with positive arteries • Ductular reaction • Sinusoidal dilatation β-IHCA • Inflamed portal-tract Retained Diffusely Diffuse or Rare positive like structures with positive “Starry sky” nuclei, may be arteries membranous • Ductular reaction • Sinusoidal dilatation β-HCA • Atypia Retained Patchy Diffuse or Rare positive “starry sky” nuclei U-HCA • Variable Retained Patchy Perivenular Membranous

©2017 MFMER | slide-55 Features • Sinusoidal dilatation • Portal tract-like structures with inflammation, multiple arteries and rare bile ductules (no true bile ducts) • No fibrous bands or larger arteries Favor inflammatory HCA C-reactive protein Glutamine synthetase

Beta-catenin LFABP Case 5:

• 40 yo female with a liver mass

• Diagnosis: Inflammatory hepatocellular adenoma (no features suggestive of beta-catenin mutation)

• Subtypes have different risk of malignant degeneration (β- HCA and β-IHCA) and associations. • But…… classification hasn’t changed treatment guidelines • Treatment algorithm: • Resect > 5cm to prevent bleeding and malignancy • Resect “adenomas” in men • Resect those growing after withdrawal of oral contraceptives

Beta catenin LFABP

• Multiple HCAs – usually greater than 10 visualized by MRI • May have many micro-nodules (usually identified by IHC) • Any subtype may occur but usually H-HCA and IHCA • Risk of malignant transformation depends on HCA subtype • When innumerable, liver transplantation may be considered

• 53 year old non-cirrhotic male with a liver mass

Mostly preserved ?Focal fragmentation

Beta-Catenin HSP-70

• 53 year old non-cirrhotic male with a liver mass.

• Diagnosis? • Beta-catenin mutated HCA in a male? • Well differentiated hepatocellular neoplasm of uncertain malignant potential/Atypical hepatocellular neoplasm? • Well-differentiated HCC?

• Well differentiated hepatocellular neoplasm of uncertain malignant potential/Atypical hepatocellular neoplasm

• On resection: try to classify definitively as either HCA or HCC

Hum Pathol. 2014 Mar;45(3):658-60.

• 60 yo male with a history of colorectal carcinoma with 5 liver lesions

Focal nodular Yes Rarely Yes Normal hyperplasia

Modern Pathology (2014) 27, 62–72

Liver international. 2009.

• 60 yo male with a history of colorectal carcinoma with 5 liver lesions

• Diagnosis: Focal nodular hyperplasia

• FNH nodules are thought to develop as localized overgrowth of liver parenchyma resulting from an anomalous arterial branch. • Cavernous hemangiomas occur in a significant % of patients with FNH • Usually > 5cm, those < 3cm may not have a central scar • OCS may promote growth • Rarely cause symptoms • Manage conservatively and only resect the rare symptomatic FNH or a lesion where the imaging is not typical