RESPIRATORY - NEOPLASIA - Updated 2022

SET 5 RESPIRATORY

Jan 2022 Dr A Chaturvedi, Consultant Histopathologist, Christie Hospital, Manchester, UK

Mass in left upper lobe bronchus male 81y

 Learning 

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About 25% of biopsy specimens of non-small cell lung cancer cannot be typed on their morphology Accurate sub-typing is important for developing ‘tailored’ therapies Immunolabelling for p40 and TTF-1 can reduce this ‘NOS’ proportion to probably about 10%

2020 WHO Classification of Lung Tumours Diagnosis in Surgically resected tumours • Squamous cell carcinomas • Adenocarcinomas • Large cell carcinoma • Sarcomatoid/Pleomorphic Ca • Neuroendocrine tumours • Carcinoids, SCLC, LCNEC • Combined tumours • Others Diagnosis in small biopsy/cytology • Small cell carcinoma • Squamous cell carcinoma • NSCC‐favour squamous (based on IHC) • Adenocarcinoma • NSCC‐favour adenocarcinoma (IHC) • NSCC‐NOS (IHC did not help) • Uncommon specific types • Descriptive, suggestive features

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Old terminologies - omitted or specifically mentioned as “Not recommended”

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Tumours with distinctive histological patterns and clinical correlates within each tumour type are designated as “subtypes”

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Newly added to each tumour entity are sections on “Diagnostic molecular pathology” and on “Essential/desirable diagnostic criteria”

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Tumour entities included in the 5th Edition are mostly unchanged from the previous edition Only few new tumor entities in the 5th Edition; viz., bronchiolar adenoma/ciliated muconodular papillary tumour (1), thoracic SMARCA4-deficient undifferentiated tumour (2), and mesothelioma in situ (3) a new IASLC grading system has been proposed In diffuse mesothelioma, two major additions

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Thoracic Tumours WHO Classification of Tumours, 5th Edition, Volume 5

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no significant changes in the classification of other types of lung cancers.

Overall, the 5th Edition will significantly improve the WHO classification system for thoracic tumours.

NSCLC

First genetic events (AdCa)

In smokers: KRAS (90%) - often followed by MET

In non-smokers: EGFR mutation 3 most common mutated genes EGFR, KRAS and ALK are mutually exclusive

First genetic events (SqCa) mutation of 3p, 9p21 (CDKN2A/ p16 TS protein) 17p13 (TP53), 13q14 (RB) Diagram adapted from: Li et al. 2013, J Clin Oncol; 31: 1039-49 & Slide presentation by Elaine Vickers, PhD | Science Communicated Ltd

Guidelines

J Thorac Oncol. doi: 10.1016/j.jtho.2017.12.001 Arch Pathol Lab Med. doi: 10.5858/arpa.2017-0388-CP J Mol Diagn. doi.org/10.1016/j.jmoldx.2017.11.004 Ann Oncol 29: 2018

Molecular – targets, tests and treatment Tumour histology and molecular pathogenesis Non-small cell lung carcinoma = 80-85%

Adenocarcinoma; Squamous cell carcinoma Adeno-squamous carcinoma; Large cell carcinoma, NOS

Small cell lung cancer

= 15-20%

Szucs TD et al. Personalized cancer medicine and the future of pathology. Virchows Arch (2012) 460:3–8.

2019ALK ihc (D5F3)/ ROS ihc +fish ?NGS panel

Molecular – targets, tests and treatment NSCLC

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EGF Receptor inhibitors ALK inhibitors Angiogenesis inhibitors Novel targets and treatments Immunotherapy: CTLA-4, PD-1, PD-L1 monoclonal antibodies

The Lung MATRIX trial (U.K.)

Courtesy : Slide modified from presentation by Elaine Vickers, PhD | Science Communicated Ltd

Molecular – targets, tests and treatment Lung cancer molecular testing guidelines The Royal College of Pathologists (UK).

Dataset for lung cancer histopathology reports, Sept 2016 Handling of small biopsies - increasingly important (following can also be applied to cell pellets derived from positive cytology specimens) Pre-examination phase•MDT discussions prior to biopsy (for molecular testing/ or also for diagnosis) •more than one block (if >1 core) Examination phase •overuse of immunohistochemistry and excessive levelling should be avoided [where indicated IHC= TTF-1, Napsin A (favour adenocarcinoma) and CK5/6, P63[or P40] (favour squamous cell carcinoma) are recommended. Mucin stains, on occasion, are also of value.]

Post-examination phase (molecular testing) Individual practice dictated by local pressuresreflex fashion for EGFR mutations versus those who order tests only after MDT discussion or request from an oncologist (LungPATH Project*) Ref., National Lung Cancer Audit Report 2013; Copyright, Health and Social Care Information Centre, UK ; and, www.hqip.org.uk/ncapop-library

Molecular – targets, tests and treatment CAP, IASLC and AMP 2013 Lung cancer molecular testing guidelines (Note: 1. only key points selected for presentations – see original document for details;

2. updated 2018) (http://www.cap.org/web/oracle/webcenter/portalapp/pagehierarchy/upcoming_cap_guidelines.jspx?_adf.ctrl-state=xeiyu68qw_4&_afrLoop=105824868952722#!)

Molecular Testing Guideline for Selection of Lung Cancer Patients for EGFR and ALK Tyrosine Kinase Inhibitors. J Thorac Oncol. 2013 July ; 8(7): 823–859.

Molecular – targets, tests and treatment Lung cancer molecular testing at Christie Hospital (UK) and also UHSM

CURRENT ROUTINE departmental practice (analysis of predictive markers): • EGFR • ALK (ROS-1) • Other (Lungcarta/Oncocarta – targeted panel approach) • PDL-1 (SP-263 ROCHE VENTANA)

PARTICIPATION IN : • Stratified Medicine Programme (SMP-phase 2) - NGS • Matrix-trial – new drug development • TRACER-X – Tumour heterogeneity

Molecular – targets, tests and treatment

Lung cancer molecular testing Christie/ UHSM (UK) experience EGFR testing *: 1. Sanger sequencing (also called direct sequencing) 2. Cobas EGFR Mutation Test (Roche): targeted detection of 41 mutations in exons 18 to 21 3. Therascreen EGFR RGQ PCR Kit (Qiagen) [not in Manchester] Manchester : (in all adenocarcinoma cases at diagnosis and on oncologist request in advanced stage disease) Sanger sequencing of samples with more than 30% tumour cells and Cobas EGFR Mutation Test for samples with lower tumour cell content

•Next-generation sequencing – screening method - sample DNA is first fragmented into a library of small segments that can be sequenced in parallel reactions [ ‘Illumina’ platform]

*EGFR-TK mutation testing in adults with locally advanced or metastatic non-small-cell lung cancer. NICE diagnostics guidance 9; August 2013

Greater Manchester Cancer Lung Cancer Protocol for Reflex Testing, 2021

Mass in left main bronchus female 50y

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Adenoid cystic carcinoma in the lung arises from seromucinous glands and is therefore confined to major airways Its histopathology is identical to its salivary counterpart It is characterised by inexorable local growth, but rarely disseminates

Mass in trachea male 58y

Chromogranin

 Learning 

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points:

Carcinoid tumours arising in airways are often vascular and capped by metaplastic squamous epithelium They almost always express neuroendocrine antigens Distinction between typical and atypical carcinoids cannot usually be made with a tissue biopsy

WHO, 2021; 5th edn: recent new data suggest the existence of multiple molecularly defined subtypes of lung neuroendocrine tumours including small cell carcinoma and large cell neuroendocrine carcinoma (1-4).

The clinical and therapeutic implication of these molecular subtypes require further studies.

1. Fernandez-Cuesta L and Foll M. Trans Lung Cancer Res 2019;8 (Suppl 4): S430-434.

2. Baine MK, et al. J Thorac Oncol 2020 Dec;15(12):1823-1835.

3. Baine MK and Rekthman N. Transl Lung Cancer Res 2020 Jun;9(3):860878.

4. Lantuejoul S, et al Transl Lung Cancer Res 2020 Oct;9(5):22332244).

Neuroendocrine tumours - spectrum Low- intermediate grade : Carcinoid (typical/ atypical)

High grade NECa - Small cell lung cancer &LCNECa

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More aggressive than NSCLC ; almost exclusively in smokers

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70-80% : metastatic disease at diagnosis

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Chemotherapy based treatment - no significant change in past 30 years

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Initial response rate 60-90% usually followed by rapid relapse and death

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Surgery in selected patients

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Emerging biomarker = IO therapies; DLL-3

Research problems/ opportunities : 

Limited access to tumour samples for analysis

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Circulating tumour cells in blood  source for research and drug development

Mass in left lower lobe female 64y

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points:

The only criteria for the diagnosis of pulmonary squamous carcinoma are keratin and intercellular bridges Pseudoglandular growth and clear cell change may cause confusion with adenocarcinoma, basaloid growth with small cell carcinoma There is no immunochemical means of distinguishing primary pulmonary from metastatic squamous carcinoma

Staging: TMN 8th edn.

Updated Appendix B TNM classification of lung cancer , RCPath Oct 2017

Mass in periphery of right upper lobe female 54y

TTF-1

 Learning 

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points:

Resected primary pulmonary adenocarcinomas should be subclassified and predominant growth pattern provided lepidic, acinar, papillary, micropapillary or solid TTF-1 is expressed by the majority of nonmucinous primary pulmonary adenocarcinomas

WHO 2021 5TH Edn: a new IASLC grading system has been proposed : Well differentiated adenocarcinoma includes lepidic predominant Adca with <20% high grade (micropapillary, solid and complex gland) patterns, while moderately Adca is acinar/papillary predominant with <20% high grade patterns.

High grade Adca = any primary pattern and 20% or more high grade patterns.

Multiple pulmonary nodules, wedge of right upper lobe female 70y

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points:

The diagnosis of in situ (lepidic) pulmonary adenocarcinoma cannot be made on the basis of a tissue biopsy, resection revealing most tumours with this pattern to have become focally invasive In situ adenocarcinoma may be mucinous, nonmucinous or mixed

Mass in right upper lobe female 82y

CD56

 Learning 

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points:

Large cell neuroendocrine carcinomas are characterised by a neuroendocrine growth pattern Some closely resemble atypical carcinoids, some small cell carcinoma Most are frankly malignant in appearance and behaviour Morphology and expression of neuroendocrine antigens

Intrabronchial mass in collapsed left lower lobe male 23y

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points:

Many intrabronchial tumours present early because of obstructive collapse and consolidation Pulmonary mucoepidermoid tumours arise from seromucinous glands and are therefore confined to the major airways Their histopathology is the same as their salivary counterparts, but their behaviour is very unpredictable

NHS (E) molecular test directory: laboratory service delivery potential implications for new tests

Discrete spherical nodule in left lower lobe female 64y

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points:

The so-called ‘chondroid hamartoma’ is now considered to be a benign, slowly growing neoplasm of mixed mesenchymal components, a mixed mesenchymoma They may develop in airways, but most present as peripheral ‘coin lesions’ that shell out from the surrounding parenchyma

One of four nodules in left lung female 67y

CK20

 Learning 

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points:

Metastatic colonic adenocarcinoma in the lung has characteristic features with widespread ‘dirty’ necrosis and tubular growth Any doubt as to the diagnosis can be usually settled by immunolabelling for TTF-1 and cytokeratins of classes 7 and 20

One of two masses in right middle and lower lobes female 62y

TTF-1

ER

 Learning 

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points:

The characteristic features of carcinoma of the breast (variably-sized, often small groups of cohesive, generally uniform cells) are usually evident in pulmonary metastases TTF-1 is useful in their differential diagnosis, but a significant proportion of primary pulmonary adenocarcinomas expresses oestrogen and progesterone receptor proteins

Mass in left lower lobe male 85y

AE1/AE3

S100

 Learning 

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points:

Metastatic malignant melanoma should always be considered in the differential diagnosis of any poorly differentiated ‘large cell’ pulmonary carcinoma Primary pulmonary melanoma does occur, but is extremely rare

Tissue from mediastinal mass, SVC compression male 75y

CD56

 Learning 

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points:

Metastasis of small cell carcinoma to mediastinal lymph nodes is common and may be its presenting feature If there is diagnostic doubt, immunolabelling for broad spectrum cytokeratins and leucocyte common antigen (CD45) is particularly useful Small cell carcinoma often fails to express neuroendocrine antigens, but NCAM (CD56) is probably the most sensitive

Tissue from discrete anterior mediastinal mass, chest pain male 34y

 Learning 

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points:

Although primary germ cell tumours of the mediastinum do occur, most are metastases of a gonadal primary Teratomas consisting entirely of mature elements are not uncommon in the mediastinum (or lung), especially after chemotherapy

Tissue from anterior mediastinal mass, chest pain female 38y

CD79a

CD3

 Learning

points:

Thoracic angiofollicular lymph node hyperplasia (Castleman’s disease) most often arises in mediastinal lymph nodes  The hyaline vascular (as opposed to plasma cell) form is usually solitary and pursues a benign course [Herpes virus type 8 (Kaposi’s sarcoma virus) may be present – in multicentric HIV associated Castleman disease] 

RN16   

Male 71 years Right pleural effusion VATS pleural biopsy 1.

2.

Full thickness pleura Pleural biopsy

RN16  Epithelioid

and spindle cell proliferation  Positive for CAm5.2, Calretinin, WT1, CK5/6, very focally for BerEP4  Negative for CEA

RN16  Epithelioid

and spindle cell proliferation  Positive for CAm5.2, Calretinin, WT1, CK5/6, very focally for BerEP4  Negative for CEA  Biphasic

malignant mesothelioma

MESOTHELIOMA Histological Types Epithelioid (60%) (tubopapillary, epithelioid, glandular, giant cell, small cell, signet ring, adenoid cystic)

Sarcomatoid (15%) (desmoplastic) Mixed or biphasic (25%) (Well differentiated papillary; In-situ)

Reporting proforma for mesothelioma biopsy/cytology specimens (Appendix C), RCPath , September 2017

Diagnostic problems Reactive versus neoplastic • Epithelioid mesothelioma vs reactive mesothelial proliferation • Desmoplastic mesothelioma versus reactive pleural fibrosis [cytologically atypical reactive mesothelium & deceptively bland mesothelioma are particular problem scenarios; (Mitoses (unless bizarre) are not entirely helpful)]

Mesothelioma or other malignancy Mesothelioma versus metastatic carcinoma Mesothelioma versus sarcoma/other [Diverse histological appearances of MM and also a common site for metastatic disease - extensive differential diagnosis]

Immunohistochemistry BAP-1 loss 5-hmC loss (5-hydroxymethylcytosine ) nuclear stain immunopanel including 5-hmC and BAP1 IHC achieved sensitivity of 98 percent and specificity of 100 percent * WHO, 2021, 5th edn: In diffuse mesothelioma, two major additions include: (1) role of BAP-1/MTAP immunohistochemistry (IHC) and CDKN2/P16 fluorescent in situ hybridization (FISH) as diagnostic markers for in situ and diffuse malignant mesothelioma, and, (2) grading system for epithelioid type diffuse mesothelioma for prognostication. The grading system is based on the degree of nuclear atypia of tumour cells, mitotic count, and presence or absence of necrosis. The new Edition will also include recommendation on the clinical reporting of mesothelioma cases. * Chapel DB, Husain AN, Krausz T. Immunohistochemical evaluation of nuclear 5-hydroxymethylcytosine (5-hmC) accurately distinguishes malignant pleural mesothelioma from benign mesothelial proliferations. Mod Pathol. 2019;32(3):376–386.

Solitary fibrous tumour •

Variably cellular

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Relatively uniform bipolar spindle or oval cells; ‘ropy’ collagenised stroma; HPC / ‘patternless’ pattern. +ve CD99, bcl2, CD34 [80%], Nuclear STAT6 (Keratin and CD31 –ve)

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malignant featuresMitoses at >4/10HPF, haemorrhage, necrosis, pleomorphism; CD34 [-ve]

De Perrot classification

[Stage 0 – 4: peduncle &benign to sessile/inverted + malignant features &mets] •

Resectability - most important prognostic indicator

CD34

Synovial sarcoma • av. age of 25 yrs (9-50) •

Biphasic (some with tubopapillary epithelial pattern) and monophasic

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No relation to asbestos exposure

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Can mimic mesothelioma (bcl-2 positive whilst mesotheliomas largely negative; calretenin maybe + in syn sa.); and, solitary fibrous tumour (rare patchy CD34 positive- difficulty with malignant SFT)

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t(X:18) translocation

Mesothelioma (epithelioid) vs other (non-epithelial) Vascular tumours • rare • Epithelioid angiosarcoma, Epithelioid haemangioendothelioma • co-expression of at least 2 endothelial markers (note - also express keratins); • mesotheliomas NOT known to express CD31, CD34, Factor VIII-RF (vWF), FLI-1 Smooth muscle tumours Sarcomatoid carcinoma (keep differential in difficult cases) Thymomas (d/d lymphohistiocytoid mesothelioma)

Malignant small tumour of thoracopulmonary region Askins/ PNET EWSa • SRCT rosettes and fibrillary tangles • Neuroendocrine marker + • mic-2 gene product (CD99) + t(11:22) translocation + –

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WT-1 negative

Differential of small round cell tumour of childhood –

RMS, SS, lymphoma, NB, Ppblastoma

Lymphomas (effusions/ occ. In biopsies) NHL - high grade (PEL/ Pyothorax associated/ DLBCL); low- grade HL -uncommon

8th Edition of the TNM staging classification for Malignant mesothelioma (also see RCPath, 2017)

• Chemotherapy: first-line chemotherapy is cisplatin &pemetrexed • Radiotherapy: limited to a single modality for palliation of symptoms90 and as part of a multimodality approach to improve local control after pneumonectomy

• Surgical – for patients with clinical stages I through III MM if they are deemed medically operable ; MARS-2 trial

Targeted therapy: • • • •

Epigenetic Modulations - histone acetyltransferases and HDACs Signaling Pathway Inhibition Role of Antiangiogenesis Immunotherapies (dendritic cell (DC) and WT1 analog peptide vaccines and antibodies targeting mesothelin)