2013 Colorado Society of Pathology Pitfalls in the diagnosis of well-differentiated hepatocellular lesions Sanjay Kakar, MD University of California, San Francisco Outline Hepatocellular adenoma: new WHO classification HCA vs. focal nodular hyperplasia HCA vs. well-differentiated HCC Benign hepatocellular lesions: pre-1990 vs. HCA Focal nodular hyperplasia Hepatocellular adenoma Focal nodular hyperplasia Hepatocellular adenoma Central scar Present Absent Fibrous septa Typically present Typically absent Nodular architecture Ductular reaction Present Generally prominent Absent Absent Clonality Polyclonal Monoclonal Telangiectatic Benign hepatocellular lesions: 1990s Focal nodular hyperplasia Telangiectatic Hepatocellular adenoma 1
Telangiectatic Hepatocellular adenoma The French Revolution Clonality studies: Monoclonal Protein profiling: cluster with adenomas Imaging: resembles adenoma Reclassified as telangiectatic adenoma Ductular reaction Fibrous septa with dystrophic arterioles Telangiectasia, inflammatory infiltrate Paradis, Gastroenterology, 2004 Benign hepatocellular lesions: pre-2008 Focal nodular hyperplasia Hepatocellular adenoma Telangiectatic or variant adenoma Hepatology. 2006;43:515-24 HCA: WHO classification 2010 HNF-1α inactivated activated HNF-1α mutation mutation JAK/STAT pathway Women, OC use Familial Marked steatosis, no atypia HCC rare 40% in men Androgens Pseudoacinar, cytologic atypia, small cell change Women (OCs), men Obesity, diabetes Inflammation, sinusoidal dilatation, ductular reaction HCC rare HNF-1α HNF-1α Mutation ve IL-6 receptor signalling Mutation negative Mutation ve Non-inflammatory Mutation-negative cases : Similar to telangiectatic adenoma Non-inflammatory: no inflammation or sinusoidal dilatation 2
Hepatocellular adenoma The French Revolution 2006: part 2 Hepatology. 2007 ;46:740-8 HCA: immunohistochemistry HNF-1α Fatty acid binding protein (FABP) FABP negative C-reactive protein (CRP) Serum amyloid associated protein (SAA) CRP+ SAA+ Glutamine synthetase () Nuclear β- catenin Diffuse HNF1α Women Steatosis Atypia, risk of HCC: minimal Fatty acid binding protein absent Unclassified (5-10%): no known defining features HNF-1α -Fatty acid binding protein (FABP) HCA: immunohistochemistry Glutamine synthetase () -C reactive protein (CRP) -Serum amyloid associated protein (SAA) Unclassified No defining features 40% men Cytologic atypia, frequent association with HCC Nuclear translocation of FABP negative Nuclear Diffuse CRP+ SAA+ 3
Normal liver: perivenular -activated adenoma: diffuse HCA: genotype-phenotype HNF1- -Fatty acid binding protein (FABP) FABP negative Beta-catenin -Beta-catenin -Glutamine synthetase () Nuclear beta-catenin Diffuse -C reactive protein (CRP) -Serum amyloid associated protein (SAA) CRP+ SAA+ hepatocellular adenoma SAA in inflammatory adenoma Inflammation Sinusoidal dilatation Ductules Pseudo-PT HCA: WHO classification 2010 HNF-1α inactivated activated 35-50% 40-50% 10% Women, OC use Marked steatosis, no atypia Women (OCs), men Obesity, diabetes Inflammation, sinusoidal dilatation, ductular reaction 40% in men Androgens, glycogen storage disease Pseudoacinar, small cell change HCC rare HCC rare HCC 40% FABP negative SAA positive CRP positive Nuclear Diffuse Unclassified (5-10%): no known defining features HNF-1α inactivated HCA classification: immunohistochemistry L-FABP SAA CRP negative negative membranous perivascular cytoplasmic positive membranous perivascular activated cytoplasmic negative nuclear diffuse Unclassified cytoplasmic negative membranous perivascular 4
Case 1: Obese 42/F with multiple (>15) liver lesions; largest (4 cm) was biopsied L-FABP L-FABP in lesion L-FABP in normal liver SAA Diagnosis HNF1α-inactivated hepatocellular adenoma Hepatic adenomatosis By definition, >10 adenomas Young women Most are HNF1α-inactivated or inflammatory Pathogenesis Obesity, less strong association with OCs Germ line HNF1α mutations Management Resection Conservative with annual surveillance Conservative with annual surveillance Management of HCA Tumor characteristics Women: solitary HCA >5 cm Men (?women>50 years): all cases activated Glycogen storage disease Solitary HCA <5 cm Multiple HCAs or adenomatosis, depending on size 5
Case 2: 53/M, 6 cm liver mass SAA positive diffuse Questions membranous, diffuse Does this represent activation? SAA+ and diffuse Is this inflammatory HCA or activated HCA? Beta-catenin: membranous : diffuse 15% of activated HCA Most have β- catenin mutation Nuclear focal or below threshold : diffuse SAA positive HCA 10% have activation Diagnosis HCA with activation 6
Immunostaining variations in HCA Variation Interpretation Membranous, diffuse activation SAA positive, diffuse, + nuclear Nuclear in few tumor cells LFABP patchy; negative in some areas Morphology not typical of inflammatory HCA, SAA positive HCA by morphology, SAA negative activation activation Does not support HNF1αinactivated HCA HCA HCA Outline Hepatocellular adenoma: new WHO classification HCA vs. focal nodular hyperplasia HCA vs. well-differentiated HCC HCA vs. : clinical significance Focal nodular hyperplasia Non-neoplastic No surgery in most cases Large, symptomatic, atypical features Hepatocellular adenoma Neoplastic Surgery if high risk features: Male, size >5 cm Risk of hemorrhage, associated HCC Case 3 32 year old woman on OCs Ultrasound for workup of abdominal pain 5 cm liver mass, suggestive of or inflammatory HCA For For inflammatory HCA Imaging favors Aberrant arterioles in fibrous septa Ductular reaction Sinusoidal dilatation Inflammation Inflammation Arterioles Few ductules Sinusoidal dilatation 7
or inflammatory HCA Immunostain HCA Serum amyloid A (SAA) Glutamine synthetase () Moderate to strong activated: diffuse Others: Perivascular/patchy Absent/focal Map-like : map-like pattern Diagnosis: Focal nodular hyperplasia SAA Histologic feature Sinusoidal dilatation HCA p value 18% 83% <0.001 Inflammation 40% 60% 0.08 Steatosis 21% 57% 0.001 Fibrous bands 90% 26% <0.001 Ductular reaction 83% 43% <0.001 Joseph/Kakar, USCAP meeting 2011 vs. IHCA: challenges in interpretation Map-like patterns on needle biopsies Map-like vs. diffuse pattern Pseudo map-like pattern SAA in and adjacent liver Use of CRP in addition to SAA : map-like : normal 8
Case 4: 40F with 6 cm liver mass : Focal map-like pattern in SAA : map-like vs diffuse HCA with SAA+ : perivascular and patchy expanded staining : pseudo map-like Joseph/Kakar, USCAP 2011 9
: Pseudo map-like Confined to periphery Patchy and variable Broad hepatocyte groups with uniform strong staining absent Case 5: 37F with 4 cm liver mass HE stain SAA+ with map-like and SAA+ SAA+ in adjacent liver SAA SAA Role of CRP SAA SAA and CRP in IHA and IHA SAA+ (>50%) CRP+ (>50%) 80% 5-10% 100% 20-25% Joseph/Kakar/Ferrell, Mod Pathol 2013 10
-like lesion Morphology and staining similar to classic Adjacent to tumors Cirrhosis Vascular abnormalities Metastatic adenocarcinoma Metastatic adenocarcinoma : Map-like HCC vs. hepatocellular adenoma Case 6 * 60/M with diabetes and renal failure CT showed a 3.9 cm mass, concerning for HCC or metastatic carcinoma, but appearance was nonspecific and can represent hepatocellular adenoma 11
Reticulin stain International Working Party Adenoma WD-HCC Wide plates (> 3) - + Small cell change - + Cytologic atypia - -/+ Reticulin Normal Fragmented Ferrell et al, Hepatology 1995 Combined immunostaining HSP70, and GPC-3: HCA vs. HCC Glutamine synthetase HSP 70 Study Lagana et al, Appl Immunohistochem Mol Morph, 2012 Nguyen/Kakar, USCAP, 2012 Results HSP70, GPC-3 <50% sensitivity 100% specific 80% sensitivity 50% specific HSP70 in 13% of HCA Overall limited utility Case 6: 58/M with 5 cm hepatic mass: biopsy 58/M with 5 cm liver mass: resection 12
Reticulin stain HCA or HCC For HCA For HCC Thin cell plates Lack of cytologic atypia Intact reticulin Age >50 years Male gender 61/M with 3.0 cm liver mass (3 yrs later) Well-differentiated HCC Beta-catenin FISH CEP1 gain. CEP8 gain Kakar/Ferrell, Histopathol, 2009, FISH by JP Grenert, UCSF 13
activated HCA, or activated HCC Morphology* HCC* Cytogenetics** Atypia: 70% Concurrent /follow-up: 40% Chromosomal changes: 60% * B Sage, Hepatol 2008 ** Evason/Kakar, Human Pathol 2012 What makes a tumor malignant? Source Webster Medical Dictionary Stedman Medical Dictionary Dorland Medical dictionary Robbins Pathology Definition Ability to invade local tissues Ability to spread to distant sites (metastasize) Is activated HCA malignant? High risk factors Local invasion (recurrence) Metastasis Pathologic features Supportive evidence Yes Yes Yes/no Yes Focal atypical morphology Pseudoacinar Small cell change Thick plates Reticulin loss Age/gender Male gender Older age (>50 yrs) Immunostaining Nuclear Diffuse Well-differentiated hepatocellular neoplasm with atypical features, HCC or activated hepatocellular adenoma HCC arising in adenoma Most activated hepatocellular tumors can be diagnosed as HCC with careful attention to morphology and reticulin staining pattern, especially in resection specimens. * 14
Reticulin HCC in adenoma Minimum stains Adenoma Stoot, HPB, 2010 studies from 1970-2009 Size >5 cm <5 cm Presence of HCC 68/1635= 4% >95% ~4% Stain Reticulin SAA Interpretation Loss: HCC Diffuse: activation Map-like: Other patterns: HCA HCA Well-differentiated hepatocellular lesion Stain Reticulin SAA Stain LFABP Beta-catenin CRP Utility HCC HCA Map-like: Diffuse: Beta-catenin Utility Glypican-3, HSP70 HCC HNF1-alpha inactivated HCA Beta-catenin Imaging features Central scar Present Absent Contrast CT enhancement Early homogenous HCA Heterogeneous and persistent MRI TI-weighted Hypointense Hyperintensity MRI T2-weighted Hypointense Strong hyperintensity 15
Feature Pitfall Approach SAA staining in peritumoral liver in needle biopsy that missed the lesion SAA negative in a lesion that shows typical features of IHA SAA positive in a lesion that shows typical features of Misinterpreted as evidence of IHA, SAA+ is not specific for IHA. especially when other peritumoral Interlobular bile ducts and absence of features like inflammation, sinusoidal diffuse CD34 staining can help in dilatation and ductular reaction are also confirming that the biopsy comprises present non-neoplastic liver. Misinterpreted as absolute evidence against IHA Misinterpreted as IHA Perivenous and patchy in a lesion that Misinterpreted as map-like pattern of shows typical features of IHA Diffuse staining Pseudo-map like pattern Misinterpreted as map-like pattern of Misinterpreted as map-like pattern of SAA can be negative in 5-10% of IHA. Imaging and absence of map-like staining is needed to confirm IHA in these cases. Focal SAA can be seen in 15% of. Map-like confirms irrespective of SAA. This staining is common in IHA. It is distinguished from map-like pattern by (i) lack of anastamosing pattern of staining. (ii) staining is heterogeneous and weak compared to homogeneous strong staining in map-like pattern. Diffuse is seen in beta-cateninactivated tumors and does not have areas of periseptal sparing of map-like pattern. Most also show nuclear beta-catenin. This is seen at the periphery of IHA and 10% of. When seen in biopsies, it is more likely to be. Diagnosis on needle biopsy may remain indeterminate if imaging and SAA are not helpful. : map-like SAA: negative or positive Compatible with vs. IHCA : resembles map-like, but not typical SAA: negative Morphology and imaging Not typical of Indeterminate : perivascular and/or patchy SAA positive IHCA SAA negative Morphology and imaging Consider CRP Likely SAAnegative IHCA : diffuse SAA: positive activated IHCA 16