Soft Tissue Tumors Flashcards
(48 cards)
What are soft tissue tumors?
Nonepithelial extra skeletal tumors
Exclude: reticuloendothelial system, glia and supporting tissue of parenchymal organs
Mesenchymal tumors are classified according to the tissue they recapitulate (muscle, fat, fibrous tissue, vessels and nerves)
What is the cause of most soft tissue tumors?
Unknown – majority occur sporadically.
Association following radiation therapy.
Rare instances following chemical burns, thermal burns or trauma.
Are any soft tissue tumors genetically associated?
Yes.
Neurofibromatosis type 1 – neurofibroma, malignant schwannoma
Gardner syndrome – fibromatosis
Li-Fraumeni syndrome – soft tissue sarcomas
Osler-Weber-Rendu syndrome – telangiectasia
Where do the majority of sarcomas occur?
About 40% occur in the lower extremities, especially the thigh.
What types of of sarcomas tend to appear in childhood? Young adulthood? Later adulthood?
Childhood: Rhabdomyosarcoma
Young adulthood: Synovial Sarcoma
Later adultlife: Liposarcoma and pleomorphic or undifferentiated sarcomas
What are a couple of important diagnostic features for soft tissue tumors?
Cell morphology
Architectural arrangement
What is the grading for soft tissue sarcoma based on?
Degree of differentiation/pleomorphism
Average number of mitoses per high-power field
Extent of necrosis (presumably a reflection of rate of growth)
What other prognostic factors are important to consider?
Size (> or < 5cm)
Depth (above or under fascia)
Stage (I-IV)
In general, tumors arising in superficial locations have better prognosis than deep lesions.
What is the treatment for soft tissue sarcomas?
Usually treated with wide surgical excision (frequently limb-sparing)
Irradiation and systemic therapy reserved for large high-grade tumors.
Adipose tissue
Lipoma
Hibernoma
Liposarcoma
Nerve
Neurofibroma
Schwannoma
Perineuriroma
Malignant peripheral nerve sheath tumor (MPNST)
Muscle
Smooth Muscle: leiomyoma, leiomyosarcoma
Skeletal Muscle: Rhabdomyoma, Rhabdomyosarcoma
Fibrous tissue
Fibroma
Fibromatosis
Fibrosarcoma
Blood vessels
Hemangioma
Hemangioendothelioma
Angiosarcoma
Miscellaneous
PVNS, myositis ossificans, angiofibroma
Synovial sarcoma, alveolar soft part sarcoma, epithelioid sarcoma
What is the most common soft tissue tumor of adulthood?
Lipoma
What are some characteristics of conventional lipomas?
The most common subtype
Soft, yellow, well-encapsulated masses
What is the histology of conventional lipomas??
Consist of mature white fat cells with no pleomorphism
What is the genetic alteration in conventional lipomas?
12q14-q15
What is one of the most common sarcomas of adulthood?
Liposarcoma
Where are liposarcomas generally located?
Deep soft tissues of proximal extremities and retroperitoneum, may develop into large tumors
How can liposarcomas histologically present and what is there behavior?
Well-differentiated is relatively indolent
Myxoid/round cell type is intermediate
Pleomorphic variant usually aggressive and may metastasize
How does a lipoblast differ from mature adipocyte?
Smaller size, has vacuolated bubbles, nucleus seems to be closer to center of cell and pushed/indented by other cells around it – indicates liposarcoma
What characterizes WD-LPS and myxoid/round LPS genetically?
WD-LPS: supernumerary ring chromosomes, amplification of 12q14-q15, containing MDM2
Myxoid/round LPS: t(12;16)(q13;p11)