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2017年1月5日 星期四

[醫如往常] Senior Clerkship Day 118: Pathology: Soft tissue tumor

Soft tissue tumor 李醫師
GIST Gastrointestinal stromal tumor
Stomach common
Vacuole nucleus
Cajal cell : c-kit RTK mutation-> cytoplasm也有
Exon 9, 11 most common
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Polygonal epithelial-like GIST
PDGFRA RTK mutation
Exon 12, 18
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HPF>20 mitosis
Size
Location: stomach prognosis good
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2nd resistance on c-kit
1st resistance on c-kit exon 13, 17


GIST的基因突變:
大約80%GIST會有酪氨酸激酶受體KIT的致癌基因突變,目前已發現GISTKIT 5個不同外顯子(exon)的基因突變-exon 11 (67%), exon 9 (10%), and exons 8, 13, and 17 (3%),而不同部位的GIST常表現不同KIT基因突變的變異,如:exon 8 (小腸)exon 9 (小腸、大腸)、而exon 11, 13, 17 (所有部位);另外約57%GIST會有PDGFRA的基因突變在exon 12, 1418的位置,通常發生在胃的GIST;然而,有1015%GIST臨床上無法測得KITPDGFRA的基因突變。

在Imitinib治療後exon 9突變的病人約2成會發展出2次的基因突變;而一開始為exon 11突變的病人則超過7成會產生2次的基因突變,而對Imitinib產生抗藥性。

Sunitinib (Sutent):為多靶標的酪氨酸激酶受體抑制劑(含:抑制PDGFVEGF受體) ,其對exon 1314突變的GIST具有療效,

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Melanoma, amelanotic type
Pagetoid spreading
c-kit +
S-100 +
EC junction, anorectal junction
Very rare


B-RAF
NF1
NRAS


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Sclerotic type well-differentiated liposarcoma
Spindle cell neoplasm
Omentum
Perigastric

dedifferentiated liposarcoma 可能並存
12q amplification
MDM2
CDK4
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Sarcomas of uncertain differentiation
Synovial sarcoma
Agrassive
t(X;18) SS18-SSX1 or SS18-SSX2 or SS18-SSX4
Biphasic pattern: spindle + gland
可以只有spindle

Ddx: GIST, MPNST

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Inflammatory pseudotumor; IPT
inflammatory myofibroblastic tumor; IMFT

borderline
multinucleated foreign body Giant cell
Lymphoplasma cells
Spindle cells (空亮的核, 明顯核仁)
Ganglion-like cells (myofibroblast)
clonal cytogenetic abnormalities involving 2p23 ALK1 staining in 40% of IMTs


Epithelial type: more aggressive

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ALK1
RTK, dimer
Over-expression, 不用ligand

常見於ATLL; Adult T-cell leukemia/lymphoma, neuroblastoma
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myxoid liposarcoma (MLS), the t(12;22)(q13;p12
Q13 CHOP
Q12 EWS

Alveolar rhabdomyosarcoma
PAX3 & FKHR (now known as FOXO1).



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