Pathology of soft tissue tumors

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Lipoma, benign

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Lipoma, benign

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Well-differentiated liposarcoma

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Myxoid liposarcoma

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Dedifferentiated liposarcoma

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Pleiomorphic liposarcoma

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Nodular fasciitis

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Deep fibromatosis/desmoid tumors

Deep fibromatosis/desmoid tumors have mutations in:

CTNNB1 (B-catenin) or APC genes —> increase Wnt signaling

Having what condition predisposes you to deep fibromatosis?

Familial adenomatous polyposis (Gardner syndrome) + APC mutation

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Embryonal rhabdomyosarcoma

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Alveolar rhabdomyosarcoma

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Leiomyoma

What gene causes leiomyomas?

FH (fumarate hydratase) gene

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Leiomyoma

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Leiomyosarcoma

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Leiomyosarcoma

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Leiomyosarcoma

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Leiomyosarcoma

What gene mutation causes Synovial Sarcoma?

SS18 gene translocations (x;18)(p11;q11) and 1/3 SSX genes

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Synovial sarcoma (biphasic due to glands presence)

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Undifferentiated pleiomorphic sarcoma

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Undifferentiated pleomorphic sarcoma

What gene mutation/translocation is in well-differentiated liposarcoma?

Amplification of 12q13-q15 on MDM2 gene.

What gene mutation/translocation is in myxoid liposarcoma?

t(12;16) translocation

What gene mutation/translocation is in myxoid pleiomorphic liposarcoma?

Losses of chromosome 13, with RB1 gene.

What gene mutation is seen in nodular fasciitis?

t(17;22) making MYH9-USP6 fusion —> clonal self-limited proliferation