PATHOLOGY OF SPINDLE CELL SARCOMAS

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PATHOLOGY OF SPINDLE CELL SARCOMAS

• Paola Collini
• Anatomic Pathology Department
• IRCCS Istituto Nazionale Tumori
• Milan - Italy

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• HISTOTYPE
• morphology immunophenotype
• ALONG THE LINE OF DIFFERENTIATION
• LEIOMYOSARCOMA SMOOTH MUSCLE
• FIBROSARCOMA FIBROBLASTS
• MYOFIBROBLASTIC SARCOMA, etc.
• WITH UNCERTAIN DIFFERENTIATION
• SYNOVIAL SARCOMA

genetics
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GRADING (G 1-3 LG vs. HG)

• REPRESENTATIVE TISSUE
• WELL FIXED AND PROCESSED TISSUE
• ONLY UNTREATED PRIMARY TUMOR
• PROGNOSTIC SIGNIFICANCE ONLY FOR CERTAIN
  HISTOTYPES (i.e., leiomyosarcoma, synovial
  sarcoma)
• USED ALSO TO PLAN THERAPY

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FNCLCC GRADING SYSTEM

• D DIFFERENTIATION 1-3
• M MITOTIC INDEX 1-3
• N OF NECROSIS 0-2
• DMN G 1-3

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LEIOMYOSARCOMA

• 2002 WHO CLASSIFICATION OF SOFT TISSUE TUMORS
• Malignant tumor composed of cells showing
• distinct smooth muscle features
• by convention, the immunocytochemical
• MODERATE/STRONG EXPRESSION
• OF AT LEAST TWO MYOGENIC MARKERS
• is required,
• otherwise we call it
• SARCOMA WITH MYOGENIC DIFFERENTIATION

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LEIOMYOSARCOMADMN G
The most differentiated form
D1
D2
D3, /- pleomorphic
The least differentiated form
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LEIOMYOSARCOMA, GRADE 3 FNCLCC
ACTIN
DESMIN
SPINDLE CELL SARCOMA, GRADE 3 FNCLCC, WITH
MYOGENIC DIFFERENTIATION
ONLY FOCAL ACTIN
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SOLITARY FIBROUS TUMOR
SYNOVIAL SARCOMA
MPNST
S100 -/ CD34 CD99
EMA CK7 bcl2 CD99 CD34 -
CD34 CD99 bcl2 EMA
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• ..................... but ..

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SARCOMA GRADE 3
DIFFERENT IMMUNOPHENOTYPE
actin
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MORPHOLOLOGICAND/OR IMMUNOPHENOTYPICHETEROGENEI
TY

• SMALL BIOPSIES
• SAMPLING OF A SURGICAL SPECIMEN
• CASES IN CONSULTATION IN WHICH NOT ALL THE
  SAMPLES ARE SUBMITTED
• PRIMARY vs. RECURRENCE / METASTASIS

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SYNOVIAL SARCOMA t(X18) SYT-SSX1 SYT-SSX2 SYT-SS
X4
MONOPHASIC TYPE
POORLY DIFFERENTIATED, SMALL CELL, EWING-LIKE
TYPE
BIPHASIC TYPE
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DERMATOFIBROSARCOMA PROTUBERANS WITH
FIBROSARCOMATOUS COMPONENT
DFSP
FS
t(1722)(q22q13) - COL1A1-PDGFbeta
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DESPITE MORPHOLOGICAND/OR IMMUNOPHENOTYPICHETER
OGENEITY

• IF THE CHARACTERISTIC GENETIC ALTERATION IS
  MAINTAINED IN THE DIFFERENT COMPONENTS,
• IT CAN HAVE
• DIAGNOSTIC VALUE
• PREDICTIVE VALUE

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paola.collini_at_istitutotumori.mi.it