Soft Tissue Tumors Flashcards
What is the cause of most soft tissue tumors?
Majority of tumors occur _________
Unknown (Documented association following rad therapy, and some rare burns( chemical and thermal) and trauma
Sporadically
Where do soft tissue tumors arise?
Any location, but 40% of sarcomas occur in lower extremity, esp. thigh
What is the relationship between soft tissue tumors and ages?
Incidence of sarcomas increases with age (15% arise in children)
What are the primary diagnostic features used? What ancillary techniques are used to aid in diagnosis?
Primary
- Cell morphology
- Architectural arrangement
Ancillary techniques:
- Immunohistochemistry
- Electron microscopy
- Cytogenetics
- Molecular genetics
What are prognostic factors for soft tissue tumors?
- Grading (I-III): Degree of differentiation, avg. number of mitoses, extent of necrosis
- Size (> or <5 cm)
- Depth (above or under fascia)
- Stage (I-IV) of tumor
- Superficial locations have better prognosis than deep lesions
What is treatment for soft tissue tumors?
Wide surgical excision (frequently limb-sparing) usually
Irradiation and systemic therapy reserved for large high-grade tumors
What is the most common soft tissue tumor of adulthood?
Lipoma
How do lipomas usually present and how are they treated?
Most are solitary lesions, mobile slowly enlarging, painless (except angiolipoma) masses
Complete excision usually is curative
What is the morphology of lipoma?
Suclassified according to particular morphological feature (angiolipoma, spindle cell, etc.) Conventional lipomas (most common) are soft, yellow, well-encapsulated masses Consist of mature white fat cells with no pleomorphism
Genetic variant for lipomas
12q14-q15
What is one of the most common sarcomas of adulthood (40-60s)?
Liposarcoma
Where do liposarcomas arise and what is their morphology?
Deep soft tissues of proximal extremities and retroperitoneum, may develop into large tumors
Well-differentiated, myxoid/round cell, and pleomorphic histological variants
What is the behavior of liposarcoma?
WD-LPS is relatively indolent
Myxoid/round cell type is intermediate
Pleomorphic variant usually agressive and may metastasize
All types recur locally unless adequately excised
What is the genetics of liposarcoma?
WD-LPS: Supernumerary ring chromosomes (amplification of 12q14-15, containing MDM2)
Myxoid/round LPS: t(12;16)(q13;p11)
What are pseudosarcomatous proliferations?
Reactive non-neoplastic lesions that develop in response to some form of local trauma or are idiopathic
Develop suddenly and grow rapidly
Hypercellularity, mitotic activity, and primitive appearance mimic sarcoma