Sarcomi e GIST - Percorsi Diagnostico-TerapeuticiRenato Cannizzaro,

Vincenzo Canzonieri, ANATOMIA PATOLOGICAAntonino De Paoli, Mara Fornasarig, GianMaria Miolo

P D T A

Surgical Pathology Based on AJCC/UICC TNM, 7 editionProtocol web posting date: October 2013Sarcoma

SOFT TISSUE: Biopsy___ Core needle biopsy___ Incisional biopsy___ Excisional biopsy___ Other (specify): ______ Not specified

Tumor SiteSpecify (if known): ___________________ Not specified

Tumor Size and Macroscopic ExtensionGreatest dimension: ___ cm+ Additional dimensions: ___ x ___ cm___ Cannot be determined (see “Comment”)

Molecular StudiesIt is important to snap freeze a small portion of tissue whenever possible. This tissue can be used for avariety of molecular analyses for tumor-specific molecular translocations that help in classifying soft tissue tumors.Approximately 1 cmof fresh tissue (less is acceptable for small specimens, includingcore biopsies) should be cut into small, 0.2-cm fragments, reserving sufficient tissue for histologic examination. This frozen tissue should ideally be stored at –80°C.

Macroscopic Extent of Tumor (select all that apply)___ Superficial___ Dermal___ Subcutaneous/suprafascial___ Deep___ Fascial___ Subfascial___ Intramuscular___ Mediastinal___ Intra-abdominal___ Retroperitoneal___ Head and neck___ Other (specify):

Surgical ProceduresIntralesional ResectionMarginal ResectionWide ResectionRadical Resection

Histologic Type (World Health Organization [WHO] classification ofsoft tissue tumors)Specify: _______________________________ Cannot be determined

Tumor Classification from BiopsiesIt is not always possible to classify soft tissue tumors precisely based on biopsy material, especially FNA and core needle biopsy specimens. Although pathologists should make every attempt to classify lesions in small biopsy specimens, on occasion stratification into very basic diagnostic categories, such as lymphoma, carcinoma, melanoma, and sarcoma, is all that is possible. In some cases, preciseclassification is only possible in open biopsies or resection specimens.

WHO Classification of TumorsClassification of tumors should be made according to the World Health Organization (WHO)Classification that divides tumors into 4 categories: benign,intermediate (locally aggressive),intermediate (rarely metastasizing),malignant.

Fibroblastic / Myofibroblastic Tumors

Intermediate (locally aggressive) Superficial fibromatoses (palmar / plantar)Desmoid-type fibromatoses Lipofibromatosis

Intermediate (rarely metastasizing)Solitary fibrous tumor Inflammatory myofibroblastic tumorLow-grade myofibroblastic sarcomaMyxoinflammatory fibroblastic sarcomaInfantile fibrosarcoma

MalignantAdult fibrosarcomaMyxofibrosarcomaLow grade fibromyxoid sarcoma/hyalinizing spindle cell tumorSclerosing epithelioid fibrosarcoma

WHO Classification of Soft Tissue Tumors of Intermediate Malignant Potential and Malignant Soft Tissue Tumors

Mitotic Rate (Note D)Specify: ___ /10 high-power fields (HPF)(1 HPF x 400 = 0.1734 mm; X40 objective; most proliferative area)

GradingThe most widely used soft tissue grading systems are the French Federation of Cancer Centers Sarcoma Group (FNCLCC) and National Cancer Institute (NCI) systems. Both systems have 3 grades and are based on mitotic activity, necrosis, and differentiation, and are highly correlated with prognosis.Accurate grading requires an adequate sample of tissue, which is not always available from FNA or core needle biopsy or in tumors previously treated with radiation or chemotherapy. However, efforts to separate sarcomas on the basis of needle biopsies into at least 2 tiers (ie, low and high grade) is encouraged. In general, multiple needle core biopsies exhibiting a high grade sarcoma can be regarded as high grade, since the probability of subsequent downgrading is remote, but limited core biopsies of low-grade sarcoma carry a risk of upgrading.

Necrosis (macroscopic or microscopic) ___ Not identified___ PresentExtent: ____%

TNM GradingThe seventh edition of the American Joint Committee on Cancer (AJCC) and International Union Against Cancer (UICC) staging system for soft tissue tumors recommends the FNCLCC 3-grade systembut effectively collapses into high grade and low grade.This means that FNCLCC grade 2 tumors are considered “high grade” for the purposes of stage grouping.

Histologic Grade (French Federation of Cancer Centers Sarcoma Group [FNCLCC]) ___ Grade 1 ___ Grade 2___ Grade 3___ Ungraded sarcoma___ Cannot be determined

The FNCLCC grade is based on 3 parameters: differentiation, mitotic activity, and necrosis. Each of these parameters receives a score: differentiation (1 to 3), mitotic activity (1 to 3), and necrosis (0 to 2). The scores are summed to produce a grade.

Grade 1: 2 or 3Grade 2: 4 or 5Grade 3: 6 to 8

MitosesScore 1: 0 to 9 mitoses per 10 HPFScore 2: 10 to19 mitoses per 10 HPFScore 3: >19 mitoses per 10 HPF

Tumor Necrosis: Determined on histologic sections.

Score 0: No tumor necrosis Score 1: < 50% tumor necrosisScore 2: ≥50% tumor necrosis

Differentiation: Tumor differentiation is scored as follows Score 1: Sarcomas closely resembling

normal, adult mesenchymal tissue and potentially difficult to distinguish from the counterpart benign tumor (eg, well-differentiated liposarcoma, well-differentiated leiomyosarcoma)

Score 2: Sarcomas for which histological typing is certain (eg, myxoidliposarcoma, myxofibrosarcoma)

Score 3: Embryonal sarcomas and undifferentiated sarcomas, synovial sarcomas and sarcomas of doubtful tumor type

Margins___ Cannot be assessed___ Margins negative for sarcomaDistance of sarcoma from closest

margin: ___ cmSpecify margin:

____________________________Specify other close (less than 2.0 cm)

margin(s): ___________________________ Margin(s) positive for sarcomaSpecify margin(s):

____________________________

E. MarginsIt has been recommended that for all margins <2 cm, the distance of the tumor from the margin be reported in centimeters.Specify the location of all margins <2 cm and the distance of the closest margin that is <2 cm.Margins from soft tissue tumors should be taken as perpendicular sections, if possible. If bones are present in the specimen and are not involved by tumor, or the tumor is >2 cm from the margin, the marrow can be scooped out and submitted as a margin.

+ Lymph-Vascular Invasion+ ___ Not identified+ ___ Present+ ___ Indeterminate

TNM Descriptors (required only if applicable) (select all that apply)___ m (multiple)___ r (recurrent)___ y (posttreatment)

Primary Tumor (pT) ___ pTX: Primary tumor cannot be assessed___ pT0: No evidence of primary tumor___ pT1a: Tumor 5 cm or less in greatest dimension, superficial tumor___ pT1b: Tumor 5 cm or less in greatest dimension, deep tumor___ pT2a: Tumor more than 5 cm in greatest dimension, superficial tumor___ pT2b: Tumor more than 5 cm in greatest dimension, deep tumor

Pathologic Staging (pTNM)

Regional Lymph Nodes (pN)___ pNX: Regional lymph nodes cannot be assessed___ pN0: No regional lymph node metastasis___ pN1: Regional lymph node metastasis

___ No nodes submitted or found

Number of Lymph Nodes ExaminedSpecify: _______ Number cannot be determined (explain): _____________

Number of Lymph Nodes InvolvedSpecify: _______ Number cannot be determined (explain): __________ __

Distant Metastasis (pM) (Note J)___ Not applicable ___ pM1: Distant metastasis+ Specify site(s), if known: ___________________

Ancillary Studies (required only if applicable)

ImmunohistochemistrySpecify: _______________________________ Not performed

CytogeneticsSpecify: _______________________________ Not performed

Molecular PathologySpecify: ____________________________ ___ Not performed

Treatment Effect___ Not identified___ Present + Specify percentage of viable tumor (compared with pretreatment biopsy, if available): ____% ___ Cannot be determined

Response to Chemotherapy/Radiation Therapy EffectTherapy response is expressed as a percentage of total tumor area that is viable. At least 1 section of necrotic tumor (always with a transition to viable tumor) should be sampled to verify the gross impression of necrosis.

Histological Classification of Treated LesionsBecause of extensive treatment effects, such as necrosis, fibrosis, and chemotherapy-induced andradiation-induced pleomorphism, it may not be possible to classify some lesions that were either never biopsied or where the biopsy was insufficient for a precise diagnosis.

Definition of Procedures

Intralesional ResectionLeaving gross or microscopic tumor behind. Partial debulking or curettage are examples or when microscopic tumor is left at the margin unintententionally in an attempted marginal resection.

Marginal ResectionRemoving the tumor and its pseudocapsule with a relatively small amount of adjacent tissue. There is no gross tumor at the margin; however, there is a high likelihood that microscopic tumor is present. If microscopic disease is identified at the margin, then it is an intralesional resection. Note that occasionally a surgeon will perform an “excisional” biopsy, which effectively accomplishes the same thing as a marginal resection.

Wide ResectionAn intracompartmental resection. The tumor is removed with pseudocapsule and a cuff of normal tissue surrounding the neoplasm, but without the complete removal of an entire muscle group, compartment, or bone.

Radical ResectionThe removal of an entire soft tissue compartment (for example, anterior compartment of the thigh, the quadriceps) or bone, or the excision of the adjacent muscle groups if the tumor is extracompartmental.

EVOLVING CLASSIFICATION OFSOFT TISSUE TUMORS:

AN UPDATE BASED ON THE NEW2013 WHO CLASSIFICATION

SIGNIFICANT CHANGES FROM 2002 CLASSIFICATION•‘MFH’ is gone

•‘Haemangiopericytoma’ is gone

•Pericytic (perivascular) tumours better defined

•GIST and nerve sheath tumours now allocated to BB volume

•Category of undifferentiated sarcomas introduced

•Some “new entities” added

•More genetic data added

World Health Organization (2013)Classification of Tumours of Soft Tissue“NEW ENTITIES”

Pseudomyogenic (ES-like) haemangioendotheliomaHybrid nerve sheath tumoursAcral (digital) fibromyxomaHaemosiderotic fibrolipomatous tumourPhosphaturic mesenchymal tumour

More Genetic Data• Low grade fibromyxoid sarcoma (LGFS)• Sclerosing epithelioid fibrosarcoma (SEF)

PURE LGFMS Most have t(11;16)(q33;p11) FUS-CREB3L2Few have t(11;16)(p11;p11) FUS-CREB3L1

Basically all are MUC4 immunopositive

PURE SEFIf MUC4 +ve (70%) – 40% have FUS rearrangement

(some with CREB3L1 or CREB3L2)MUC4 -ve – FUS negative, otherwise unknown

HYBRID LGFMS/SEFAll are MUC4 +ve – Most have either FUS or EWSR1

rearrangement (usually with CREB3L1)

In LGFMS/SEF, FUS rearrangements account for >90% of the fusions, whereas EWSR1 rearrangements seem distinctly more common in primary pure SEF. As SEF is decidedly more aggressive than LGFMS, this difference may be clinically important.

GIST: A Brief Modern History

•1998 – KIT activating mutations

•1998 – KIT immunoreactivity

•2002 – imatinib mesylate (gleevec) randomized trial

•2003 – PDGFRA activating mutations

• 2006 – sunitinib malate (sutent) randomized trial

•2007 – SDHB, SDHC, SDHD mutations in Carney-Stratakis syndrome

• 2008 – BRAF V600E mutations in GIST

• 2009, 2012 – adjuvant imatinib after resection of localized GIST – randomizedTrials

• 2011 – SDHA mutations in sporadic GIST

• 2013-2015 – genotyping to guide TKI therapy?

Ronald P. DeMatteo, MD FACS.

Mutations and clinicopathological featuresGenes Exon Frequent mutations Frequency Characteristics and site Imatinib

sensitivity

KIT All exons8

80 %Rare5–10 %

All sitesSmall bowelSmall bowel, colon, spindle, aggressive

Yes,intermediate9 Insertion of AY

502–503Deletions, missense mutations, insertionsDeletion of codon 557 or 558Internal tandem duplicationK642ED820Y, N822K, Y823D

11 60–70 % All sites Yes

Aggressive, poor prognosis

Benign features, clinically indolent, female, stomach

1317

1 %1 %

All sitesAll sites

YesNo forD816V

PDGFRA All exons 10 %1–2 %\1 %10–5 %

Epithelioid, clinically indolentAll sitesStomach, epithelioidStomach, mesentery, omentum, epithelioid

121418

Missense mutations

N659K D842V

YesYesNo for

D842VProbably noWild-type

BRAF SDHA/SDHB/SDHC/SDHD mutations

10–15 %Rare*2 %

All sitesV600E

Carney–Stratakis syndromea; stomach, multiple, immunohistochemically SDHB negative

Juvenile GIST; stomach, clinically indolent, multiple, immunohistochemically SDHB negative

Carney triadb; stomach, clinically indolent, juvenile onset, immunohistochemically SDHB negative

Loss of SDHexpression

HRAS, NRASmutation

NF1 mutation

\1 %

1–2 % Small bowel, clinically indolent, multiple, spindle

SDH succinate dehydrogenase, SDHB succinate dehydrogenase iron–sulfur subunit (subunit B)a Carney–Stratakis syndrome: familial syndrome of multiple GIST and paragangliomas with autosomal dominant inheritance and germlinemutation in the SDH complexb Carney triad: coexistence of gastric gastrointestinal stromal tumor (GIST), pulmonary chondroma, and extra-adrenal paraganglioma in youngwomen, postulated to be defect in expression of the SDH complex

no

no

Succinate Dehydrogenase Complex

Ricketts et al. J Urol. 2012

Succinate Dehydrogenase in GISTs•IHC for SDHB: loss of normal cytoplasmic (mitochondrial) staining in CarneyStratakissyndrome-associated GISTs

Similar findings observed in pediatric,Carney triad-associated, and adult multinodular “wild-type” gastric GISTs

IHC for SDHB is a good screening tool for identifying this clinically distinctive class of gastric GISTs: SDH-deficient GISTs

IHC for SDHB and Genotype

Doyle et al. Histopathology. 2012

SDHB

KIT exon 11-mutant GIST

SDHB

SDH-deficient GIST

GIST post-imatinib

Morphologic shift associated with aberrant cytokeratin

expression in a long-surviving GIST patient after multimodal

therapy. A case report with a brief review of the literature.

Vincenzo Canzonieri1 , Daniela Gasparotto2, Lara Alessandrini1

,Gianmaria Miolo3, Elena Torrisi3, Tiziana Perin1 , Paolo De

Paoli4 , Roberta Maestro2, Angela Buonadonna3

Ms. Ref. No.: PRP-D-15-00299R2 Title: Morphologic shift associated with aberrant cytokeratin expression in a GIST patient after tyrosine kinase inhibitors therapy. A case report with a brief review of the literature. Pathology - Research and Practice Dear Dr.Med. Lara Alessandrini, I am pleased to inform you that your paper "Morphologic shift associated with aberrant cytokeratin expression in a GIST patient after tyrosine kinase inhibitors therapy. A case report with a brief review of the literature." has been accepted for publication in Pathology - Research and Practice. Thank you for submitting your work to Pathology - Research and Practice. Yours sincerely, Albert Roessner Editor Pathology - Research and Practice

CT scan

CD117

•The tumor cells are uniform and spindling with ill-defined cytoplasmic border

•The nuclei are spindle and sometimes embedded in a fibrillary background

•Necrosis is present

Pancreatic GIST

CD117 DOG1

Pancreatic GIST

Esophageal GIST

CD 34PDGFRA

CD117