IHC And Special Stains In Daily Practice. Dr Ian Brown Envoi Pathology Brisbane, Australia

Transcription

1 IHC And Special Stains In Daily Practice Dr Ian Brown Envoi Pathology Brisbane, Australia

2 Why do special stains? Tumour Classify disease Prognostication Predict response to therapy Identify an inherited syndrome Identify primary site of origin Inflammatory pattern Look for infective cause Classify the immune reaction Exclude a haematological neoplasm Classify disease Never do a special stain without knowing what to do with the result I also like to get personal experience with special stains so that I know how they will work when I really need them

3 Overview IHCs Gastrin H.pylori Use of p53 CD3/8 for RCD MMR stains MLH-1 in SSAD Detection of enteroblastic differentiation Vascular invasion markers SATB2 DLBCL subtyping Β catenin What I don t do!! New and evolving concepts/general discussion Reference: An Update on the Role of Immunohistochemistry in the Evaluation of Gastrointestinal Tract Disorders. Adv Anat Pathol Sep 18.

4 Gastrin for autoimmune gastritis Features of AI gastritis

5 Gastrin for autoimmune gastritis Some cases have minimal or no intestinal metaplasia minimal or no history Just labelled as gastric

6 Gastrin for autoimmune gastritis

7 Gastrin for autoimmune gastritis Always do a H.pylori stain also Co-existence mimic? NE stains (synaptophysin) increase the diagnostic yield

8 Atrophic pattern of collagenous gastritis

9 Atrophic pattern of collagenous gastritis

10 H.pylori Not routinely! Selective use and not if clearly evident on the H&E active gastritis and gastric ulceration (unless clearly reactive gastropathy associated) moderate/florid chronic gastritis (? mild chronic gastritis) Autoimmune gastritis Lymphocytic gastritis (look very carefully!!) MALT lymphoma Previous H.pylori Positive urease Gastric intestinal metaplasia Gastric adenocarcinoma Duodenal ulceration

11 H.pylori

12 Use of p53 Barrett s dysplasia IBD dysplasia

13 p53 in Barrett s dysplasia British Society of Gastroenterology guidelines on the diagnosis and management of Barrett s oesophagus Gut 2014;63:7 42. The addition of a p53 immunostain to the histopathological assessment may improve the diagnostic reproducibility of a diagnosis of dysplasia in Barrett s oesophagus and should be considered as an adjunct to routine clinical diagnosis (Recommendation grade B) I dabble! But I work in the ideal situation and the result of p53 seldom changes what I will call the atypia

14 p53 in Barrett s dysplasia However, there may be a role in the following situations 1) Isolated practice 2) Limited experience with BE dysplasia 3) Triage to know what is worth sending on 4) The stakes are high Procedure will follow It might be adenocarcinoma versus just reactive

15 p53 in Barrett s dysplasia Our data on use of p53 in indefinite for dysplasia (retrospective) 125 indefinite cases with Strong p53 in indefinite Weak p53 in indefinite follow up biopsies focus focus No dysplasia 8 76 Persisting indefinite 1 18 No progression 9 94 LGD 1 7 HGD/IMCA 9 5 Dysplasia ~1/2 of our indefinite cases with strong p53 represented true dysplasia (usually HGD/IMC) while only ~ 10% represent no dysplasia/persisting indefinite

16 p53 in Barrett s dysplasia Patterns Over-expression Loss of expression Courtesy of Priyanthi Kumarasinghe

17 p53 in IBD dysplasia AJG 2011

18 p53 in IBD

19 CD3/8 in refractory coeliac disease Disease not responding (or recurring) after 12 months of GFD or severe or deteriorating clinical symptoms Need to consider Inadequate GFD Wrong diagnosis Another condition causing the symptoms Slow responding coeliac disease (RCD type 1) Development of a clonal intraepithelial T cell process (RCD II) At high risk of progression to type 1 EATL

20 CD3/8 in RCD Response to GFD Author Number Marsh 0 (%) Marsh 1/2 (%) Marsh 3 (%) Bardella Hutchinson Martini Ciacci Lanzini Wahab Tuire Haere Range 8 81% 14 71% 4 62%

21 Refractory coeliac disease TCR rearrangement CD3/CD8 immunohistochemistry Flow cytometry Celiac disease Polyclonal Preserved No loss of surface T cell markers RCD1 Polyclonal (usual) Preserved No loss of surface T cell markers RCD 2 Monoclonal CD8 lost in > 50% of CD3 positive IEL Loss of surface CD3, CD7 and CD8 in > 20% of IEL

22 Refractory coeliac disease

23 MMR stains in CRC 2 reasons 1) Detect Lynch syndrome 2) Indicate response for PD-1 inhibitors? Universal testing or selective

24 Universal MMR testing at Envoi 2,077 consecutive CRCs tested for MMRP status over 5 years From 2,016 patients with a median age at diagnosis of 70 years females 45.5% MMR protein deficiency in 399 cases (19.2%)

25 MMR IHC in adenomas Little benefit In known Lynch syndrome patients Up to 70% of adenoma in LS show loss of corresponding MMR protein Higher rate in advanced adenomas: high grade dysplasia, villous component Normal MMR IHC expression does not exclude Lynch syndrome Best option: if known CRC in the family, test the cancer and test family members if a mutation is identified No indication for HP and SSA (but we have seen TSA s in with MMR loss in Lynch syndrome) Ferreira S et al. Dis Colon Rectum 2008;51: Walsh MD et al. Mod Pathol 2012;25:

26 Significance of common MMR IHC patterns Pattern of IHC expression Probability of LS Significance All 4 MMR proteins (or PMS2/MSH6) normal Very unlikely Normal pattern. No further testing, unless strong clinical suspicion (MSI testing) MLH1/PMS2 loss Sporadic or LS BRAF mutation testing If present: Stop sporadic CRC If absent: MLH1, followed by PMS2 germline testing MSH2/MSH6 loss Likely MSH2, followed by MSH6 germline testing MSH6 loss Likely MSH6, followed by MSH2 germline testing PMS2 loss Likely PMS2, followed by MLH1 germline testing. Could a MLH-1 mutation with sufficient protein to be immunoreactive but non functional MLH1/PMS2 loss and MSH6 loss (partial or complete) Very unlikely MLH-1 hypermethylation with a secondary mutation in a coding region of MSH6 All 4 MMR proteins lost Likely Germline loss of MSH2 and hypermethylation of MLH-1

27 MMR stains in CRC Can get biallelic sporadic loss of MMR protein vs constitutional biallelic loss of MMR protein Also somatic mosaicism (FAP) A side point: Not all Lynch is the same PMS2 Lynch is commonly present but infrequently presents with clinical disease Good review on MMR IHC patterns = Immunohistochemical Pitfalls: Common Mistakes in the Evaluation of Lynch Syndrome. Surgical Pathology Clinics 10 (2017)

28 MLH1 in SSA/D We do not do this routinely but actually quite a bit because we garnering experience, particularly with minimal deviation types Also, to get better at picking between early TSA arising in a SSA versus serrated pattern dysplasia, NOS (which is more biologically aggressive) Note MLH-1 may be lost in occasional non dysplastic crypts in otherwise typical SSA ( SSA/D) (also isolated non dysplastic crypts adjacent to Lynch syndrome cancers may show loss of MMR protein) Mod Pathol Oct;31(10):

29 Pathways to BRAF mutant colorectal carcinoma MLH1 loss SSAD MSI SSA SSAD MSS MLH1 preserved Uncertain TSA?p53 P53, p16 BRAF MSI CRC BRAF MSS CRC

30 MLH1 in SSA/D usual/nos type

31 MLH1 in SSA/D minimal deviation

32 MLH1 in SSA/D - serrated

33 Detection of enteroblastic/foetal type differentiation αfp producing tumours of the upper GIT (often stomach) (1) hepatoid type (2) yolk sac type (3) enteroblastic type foetal or Enteroblastic type: (1) columnar carcinoma cells growing primarily in tubulopapillary and glandular patterns (2) abundant glycogen, but no mucin production in the clear cytoplasm (3) gut hormone-containing cells scattered among clear carcinoma cells (4) carcinoma cells producing oncofoetal glycoproteins such as αfp, SALL 4, glypican 3 and CEA (5) ultrastructurally, carcinoma cells showing well-developed microvilli with core filaments, whose rootlets formed occasional terminal webs, consistent with absorptive epithelium of foetal intestine or enteroblastic differentiation.

34 Detection of enteroblastic/foetal type differentiation αfp

35 Detection of enteroblastic/foetal type differentiation Importance Production/expression of αfp Poor prognosis?under recognised (often a component of otherwise typical adenocarcinoma)

36 Vascular invasion markers Lymphatic invasion (LI) and venous invasion (VI) are important Px markers in all GIT malignancies LI is and adverse factor in all luminal pt1 tumours usually an indication for extended resection VI is a factor suggesting CT for stage II CRC VI is a quality marker for CRC reporting RCP structured report Sept 2018 = At the current time, individual units should closely monitor venous invasion rates and, if they are consistently below the 30% threshold, then the adoption of elastic staining as standard is recommended

37 Vascular invasion markers

38 Vascular invasion markers What to do: LI D2/40 ( not of much benefit) VI Orcein* Other elastin stains e.g. VVG Desmin Other?

39 Vascular invasion markers

40 SATB2 Transcription factor Osteoblasts, colorectum, appendix, some urothelial/renal Personally usefulness has been limited (vs cdx2) but can be synergistic Peritoneal disease of unknown primary especially if signet ring morphology or goblet cell adenocarcinoma Ovarian adenocarcinoma Occasional liver metastases Often lost in MMR deficient CRC

41 SATB2 IBD related neoplasia

42 Β catenin Hepatocellular adenoma typing Solid cystic pseudopapillary tumour of pancreas Fibromatosis Conventional adenoma vs reactive (e.g. at ampulla) Foveolar dysplasia in FGPs morules

43 Β catenin

44 Β catenin

45 DLBCL subtyping Covered in current WHO Hans classifier [CD10, bcl6, MUM1; 30% IHC positivity cut off for each] Germinal centre cell like Better Px CD10 +, bcl6 +, MUM1 Activated B cell like Worse Px CD10 -, bcl6 +, MUM1 More aggressive therapy Also search for double/triple hit lymphoma (5-15%) = Ki67 >90% C-myc IHC ± progress to FISH (also include bcl2 and bcl6) Think of EBV association

46 What I don t do (usually) PAS stain for candida (often) Alcian blue/other for detection of goblet cells in Barrett s oesophagus Collagen stains in most cases of collagenous colitis Desmin stain for small colorectal leiomyoma Stains for fibroblastic polyp of colon Panels for bland mesenchymal tumours of GIT

47 Evolving concepts?mmr testing in all adenocarcinomas Detect MSI predict response to PD1 inhibitors (also detects Lynch syndrome) Tumour type Frequency, % (n) Colorectal cancer 13% (1066) Endometrial 22% (543), 33% (446) Gastric 22% (295) Hepatocellular carcinoma 16% (37) Ampullary carcinoma 10% (144) Thyroid 63% (30) Skin (sebaceous tumors) Skin (melanoma) 11% (56) 35% (20), 60% (25) Tumor type Frequency, % (n) Ovarian 10% (1234) Cervical 8% (344) Esophageal adenocarcinoma 7% (76) Soft-tissue sarcoma 5% (40) Head and neck SCC 3% (153) Renal cell carcinoma 2% (152) Ewing sarcoma 2% (55) Clin Cancer Res; 22(4);

48 Evolving concepts MUC stains Barrett s dysplasia/gastric dysplasia classification Gastric type adenomas Other (EMA)

49 Evolving concepts Anything else??? Her2 in CRC