Biliary Tract Neoplasia: A Cyto-histologic Review. Michelle Reid, MD, MSc Professor of Pathology Director of Cytopathology Emory University Hospital

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1 Biliary Tract Neoplasia: A Cyto-histologic Review Michelle Reid, MD, MSc Professor of Pathology Director of Cytopathology Emory University Hospital

2 Bile Duct Brushings (BDB) BDBs are the initial diagnostic test for biliary tract lesions Limitations include: Low sensitivity of 35% (6-64%) in diagnosing malignancy Procedural problems: Technical difficulty, site s anatomic complexity Interpretative issues: Atypia related to ulceration, inflammation and stents is frequent Some carcinomas can be cytologically subtle

3 Our experience with BDBs Cytology database of > 600 BDBs 253 cases with follow up Additionally, imitation brushing of Whipple specimens were performed in > 60 cases in order to obtain direct cyto-surgical correlation Cytologic criteria and level of inter-observer agreement were tested in 60 BDBs by 7 pathologists

4 11 of the 14 published criteria are diagnostically valuable FREQUENCY (%) OF CHARACTERISTICS AMONG BENIGN AND MALIGNANT BILE DUCT BRUSHINGS Benign Malignant p< p< p= p< p< p< p= p< p= p= p=0.005 p<0.009 p= Necrosis, mitosis and inflammation are NOT HELPFUL (in our experience)

5 #1: Nuclear Pleomorphism

6 #2. 3-Dimensional Clusters 80 P< P < % 70% Malignant Benign % 3-D clusters 10% P= % Prominent nucleoli

7 #1: Other Examples of 3-Dimensional Clusters

8 #3. High Nuclear to Cytoplasmic Ratio

9 #4. Change in Chromatin Pattern 80 P< P < % 70% P= Malignant Benign 0 3% 10% 21% 3-D clusters Chromasia Prominent nucleoli

10 #4. Change in Chromatin Pattern: Carcinoma HypERchromasia HypOchromasia

11 #5. Single cells with high nuclear to cytoplasmic ratio Due to cellular dissociation P= % 3% Single cells w/ high N/C (>50%) Malignant Benign

12 #6. Nuclear Contour Irregularity

13 #7. Cytoplasmic mucin vacuoles 60 P= % 13% Cytoplasmic mucin vacuoles Malignant Benign

14 2-cell population is also very helpful for diagnosing carcinoma P< % P< % Malignant Benign Malignant cells Benign cells % 2-cell population High N/C

15 However there are definite exceptions and challenging cases 1. These cytologic features are not definitive when used individually 2. Several cytologic features are better than 1 feature alone Mod Pathol Sep;30(9):

16 Our analysis: Identification of 3 or > of the 11 criteria achieves the best balance of test accuracy Cut point Sensitivity Specificity Accuracy 0 compared to compared to compared to compared to compared to compared to compared to compared An to increasing 8 number 40 of malignant characteristics 100 progressively 70 improves specificity but naturally sensitivity goes down 8 compared to compared to

17 Example of a benign case with detachment atypia misdiagnosed as malignant 70 year-old female: 2/3 cytopathologists identified 9 malignant characteristics in this BDB. FOLLOW-UP 2011: Bile duct Bx: Benign. Clinical follow-up: 55 months Final outcome: Benign

18 Severe benign detachment atypia (mimicking carcinoma) Note absence of definite 3-D clusters and relatively low N/C ratio, flat curled epithelial strips Atypia is due to mucosal ulceration/erosion with epithelial detachment

19 Interesting Case Presentation Atypia Nuclear enlargement Chromatin clumping Worrisome cytology However, Cells are arranged in flat sheets Smooth nuclear contours N/C ratio relatively low Prominent nucleoli (reactive type) Each nucleus resembles the other = REACTIVE ATYPIA 61 year old obese female with jaundice, common bile duct strictures, no mass

20 Same Case One population in honeycomb sheets: Benign cells Arranged in flat sheets Nuclear enlargement Two-cell population Nuclear pleomorphism N/C ratio getting higher Prominent nucleoli Coarse chromatin Cellular discohesion = ATYPIA, NOS Another population of crowded cells with large nuclei Cellular discohesion Prominent nucleolus

21 Flat sheet Note striking nuclear enlargement and pleomorphism Irregular nuclear borders Prominent cytoplasmic nuetrophilcs Cell block from the same patient Coarse chromatin Relatively low N/C ratio Prominent nucleoli Cytoplasmic vacuoles = MALIGNANT: ADENOCARCINOMA Two key points: 1. Neutrophils are not only seen in benign inflammatory conditions, but also in neutrophil-rich carcinoma 2. Some adenocarcinomas have low N/C ratio

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23 Example of a neutrophil-rich carcinoma

24 Use of Biopsy and Ancillary Studies in Indeterminate BDBs Bile duct biopsy is superior to brushings in 60% of cases FISH: Urovysion FISH New pancreatobiliary FISH probe set Higher sensitivity than UroVysion (65% vs 46%) and cytology (19%), but similar specificity (93%) MCL1 (chr1q), EGFR (chr7p), MYC (chr 8q) oncogenes p16/cdkn2a TSG on chr 9p21 Deleted in dysplasia and invasive pancreatobiliary cancers Immunohistochemistry - UNRELIABLE S100P, IMP3, mcea are positive in carcinoma SMAD4, pvhl (lost/negative in carcinoma) P53 +/- Molecular studies: KRAS (90%), DPC4 (25%), CDKN2A (17%), P53 (60%)mutation I have no relationship with any of the vendors or products mentioned.

25 Biopsy has higher sensitivity (69%) and accuracy (80%) than BDB (42% and 69%, respectively) in predicting malignancy BDB read as atypical cells BDB read as atypical cells Biopsy read as adenocarcinoma Biopsy read as adenocarcinoma

26 Conventional Intraepithelial Neoplasia FLAT Conventional dysplastic processes like CIN/SIL of cervix MASS-forming Pre-invasive neoplasia such as colonic adenomas

27 FLAT-TYPE Intraepithelial Neoplasia of the Biliary Tree

28 Pancreatic Intraepithelial Neoplasia Biliary Intraepithelial Neoplasia PanIN BilIN

29 BilIN, Zen et al, Modern Pathology,

30 IGNORE NOT GOOD BilIN/Dysplasia: Clinical significance BilIN 1, 2 LOW-GRADE BilIN 3 HIGH GRADE

31 Biliary Intraepithelial Neoplasia (Dysplasia) Factors/context/etio-pathogenesis Established risk factors: Inflammation Dysplasia Parasites Carcinoma sequence It is sometimes difficult to Lithiasis tell where regeneration Primary sclerosing cholangitis ends and neoplastic Choledochal cyst transformation begins Others Dysplasia/Carcinoma is regeneration gone wrong (out of control)

32 Diagnostic problem #1: Reparative atypia vs Dysplasia

33 Diagnostic problem # 2: Colonization vs BilIN-3/CIS

34 Most BilIN3 (HGD/CIS) are detected incidentally 1. Adjacent to invasive carcinoma 2. In high-risk lesions such as choledochal cysts

35 Choledochal Cyst A clinically defined entity Most of the literature on Choledochal cysts is from Asia Marked definitional differences between Asia and West Associated with increased risk of cancer Risk is fairly high in Asia If cysts are > 1 cm Risk is low in the West

36 BilIN-3 (HGD/CIS) is seen in ~ 15% of resected choledochal cysts (84 cases)

37 Invasive carcinoma in a choledochal cyst 7% of cases

38 Severe atypia mimicking dysplasia (9 of 84 cases)

39 Intraductal papillary neoplasm (IPNB)

40 Most BilIN3 (HGD/CIS) are detected incidentally If seen adjacent to invasive carcinoma or in high- risk lesions (cysts) Is it at the margin? Implications? Investigate the specimen Sample more extensively Notify clinicians/follow closely

41 TUMORAL-TYPE Intraepithelial Neoplasia (Adenomatous/papillary neoplasms)

42 Case for Discussion 82yo, F MRI : 3.0 cm intraductal mass at the confluence of Rt and Lt hepatic ducts Pre-operative Dx: Complex cholangiocarcinoma EUS-FNA performed

43 Hypercellular smears with large sheets with vague branching papillae- Papanicolaou stain Focal peripheral palisading of cells

44 Cell block Cell block was hypercellular with branching papillae and focal cytoplasmic mucin

45 Cell block Marked nuclear irregularity

46 Cytologic Diagnosis Neoplastic cells present. Intraductal papillary neoplasm of the bile duct (IPNB) With high-grade dysplasia No definite invasive carcinoma (not cholangiocarcinoma Papanicolaou Society Guidelines IV) Neoplastic: Benign Other IPMN, MCN (mucinous cysts) IPNB NET-WD, SPN Diagnostic Cytopathology. 2014;42:

47 INTRAEPITHELIAL NEOPLASIA Dysplastic processes like CIN/SIL of the cervix FLAT (NON-TUMORAL) Mass-forming preinvasive neoplasia such as colonic adenomas TUMORAL (ADENOMA-CA)

48 Tumoral Intraepithelial Neoplasia of Biliary Tract (Mass-forming pre-invasive neoplasia) 1. IPNB (Intraductal papillary neoplasms- IPMN counterparts) 2. If they are oncocytic = IOPN (Intraductal oncocytic papillary neoplasm) 3. ITPN (Intraductal tubulopapillary neoplasms) Kindred (conceptually very similar, a form of TIN)

49 Cell block IPN-B (Intraductal Papillary Neoplasm of the Bile Duct) CBD PD Bile duct brushing

50 Gastric MUC5AC + IPNB Epithelial subtypes Intestinal Biliary MUC2+/CDX2+/CK20+ MUC1 + Oncocytic IOPN MUC6 +

51 Tumoral IN of Biliary Tract (Mass-forming pre-invasive neoplasms) 1. IPNB (Intraductal papillary neoplasms- IPMN counterparts) 2. (1B?) IOPN (Intraductal oncocytic papillary neoplasms)

52 Tumoral IN of Biliary Tract (Mass-forming pre-invasive neoplasms) 1. IPNB (Intraductal papillary neoplasms- IPMN counterparts) 2. (1B?) IOPN (Intraductal oncocytic papillary neoplasms) 3.Intraductal tubulopapillary neoplasms (ITPN) ITPN composed of back to back non-mucinous glands Often show unusual infiltration Example with comedo necrosis

53 ITPN MUC MUC6 ++ *MUC5AC -- MUC2 - Distinct molecular alterations MUC5AC negativity is definitional, but may be not

54 Invasive carcinoma is detected in > 60% of resected IPNB 10% of EHBD cancers arise from IPNB

55 TIN (IPNB/IOPN/ITPN) - associated invasive carcinomas are more indolent 1. Earlier detection (patients present with jaundice) 2. Unusual types 3. Different molecular pathways 4. Different biology It is important to report the presence of a TIN component in a case with invasive carcinoma of the biliary tract

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57 Intrahepatic Cholangiocarcinoma (ICC: New Proposed Sub-classification Am J Surg Pathol. August 2016;40:

58 Small duct type, more peripheral Large duct type, more hilar/central/distal SDT Liau, 2014

59 Intrahepatic cholangiocarcinoma (ICC), small duct type 66 yo M 8.6cm liver mass Peripheral Rt lobe Liver core

60 Intrahepatic cholangiocarcinoma (ICC), large duct type, 5cm central mass in liver Smear shows large pleomorphic malignant cells Cell block S100P is positive in malignant glands DPC4 is lost in malignant glands

61 Am J Surg Pathol. August 2016;40: Overall Survival Probability of survival P<0.001 Type 2 ICC Type 1 ICC Large duct-type Small duct-type Time after surgery (days)

62 Cholangiocarcinoma: Molecular Alterations Intrahepatic cholangiocarcinoma 30% have mutations in chromatic remodeling genes ARID1A, BAP1, PBRM1 KRAS mutation: Large duct type (23%) > small duct -type (1%) IDH1 (8%) and IDH2 (2%) mutations: Small duct (Cholangiolar) type > Large duct(bile duct) type AGI-6780, AGI-5198 molecular inhibitor

63 CONCLUSIONS Biliary brushings are challenging but application of set cytologic criteria can improve diagnosis High-grade dysplasia (BilIN-3) is is rarely seen in isolation Multifocality / field-defect (effect) phenomenon is common Thorough sampling is crucial Tumoral intraductal neoplasms (IPNB, IOPN, ITPN) show indolent behavior IPNBs have multiple cell lineages ~ 60% are invasive at resection New (small vs large duct) classification for intrahepatic cholangiocarcinoma