Soft Tissue Tumors (Rao) Flashcards
Approximately what percentage of all soft tissue tumors are sarcomas/
~1%
Benign tumors, mostly lipomas and hemangiomas, outnumber sarcomas by 100:1
What is the most common etiology of soft tissue tumors?
Unknown (idiopathic) or sporadic
Name (4) genetic syndromes associated with soft tissue tumors
- Neurofibromatosis type 1 (neurofibroma, malignant schwannoma)
- Gardner syndrome (fibromatosis)
- Li-Fraumeni syndrom (soft tissue sarcomas)
- Osler-Weber-Rendu syndrome (telangiectasia)
Rhabdomyosarcoma chiefly affects what patient population?
children
Synovial sarcoma tends to appear in what age group?
Young adults
Grading of a soft tissue tumor is primarily based on what criteria?
- Degree of differentiation/pleomorphism
- Average number of mitoses per high-power field
- Extent of necrosis
Tumors arising in which of the following locations is generally associated with a better prognosis?
- Superficial locations
- Deep lesions
Superficial locations
The presence of multiple lipomas is suggestive of what?
rare hereditary syndromes
What is the most common type of soft tumor found in adults?
Lipoma
True/False: complete excision of a lipoma is usually curative
True
Classify the following types of liposarcoma based on degree of aggressiveness
- Myxoid/round
- Well-differentiated liposarcoma (WD-LPS)
- Pleomorphic
- Myxoid/round - usually intermediate aggressiveness
- WD-LPS - Relatively indolent
- Pleomorphic - usually aggressive and may metastasize
At what anatomical locations are liposarcomas usually found?
Deep soft tissues of proximal extremities
Retroperitoneum
Identify:
- a reactive non-neoplastic lesion that develops in response to trauma (or idiopathic). Develops suddenly and grows rapidly.
Pseudosarcomatous proliferation
**often mistaken for sarcoma
Identify: A pseudosarcomatous proliferation that occurs in the deep dermis, subcutis, or muscle. Several centimeters in diameter with poorly defined margins.
Nodular fasciitis
What is myositis ossificans?
- Presence of metaplastic bone within muscle
- Due to trauma in >50% of cases
- Occurs in proximal extremities, usually young adults
- Usually well-circumscribed (unlike osteosarcoma)
What is a desmoid tumor?
A deep-seated fibromatosis
Begavior of desmoid tumors lies somewhere between that of fibrous benign tumors and low-grade fibrosarcomas
Desmoid tumors frequently recur, even after complete excision
What is the most common age range for desmoid tumors?
teens to age 30
Desmoid tumors are occasionally associated with what genetic syndrome(s)?
Gardner syndrome
Also associated with mutations in APC or ß-Catenin genes
A superficial fibromatosis of occurring on the penis is called what?
Peyronie disease
A superificial fibromatosis of the palmar surface of the hand is called what?
Dupuytren contracture
Describe the general properties of a fibrosarcoma
- Malignant tumor composes of fibroblasts
- Occurs most often in adults
- Generally found in the deep tissues of the thigh, knee, and retroperitoneum
- Generally aggressive - recur in 50% of cases, with metastasis in 25% of cases
Name the disease associated with the following immunohistological marker(s):
- (+) vimentin
- all others negative
Fibrosarcoma
What is the most common neoplasm found in women?
Uterine leiomyoma
What type of sarcoma exhibits the following immunohistological markers?
- (+)SMA
- (+)Desmin
Leiomyosarcoma
Describe the properties of Leiomyosarcoma, including:
- major patient population
- common anatomic location(s)
- prognosis
- immunohistochemical staining
- Adults, F>M
- Location: skin and soft tissues of extremities and peritoneum
- Prognosis: superficial associated with good prognosis. Retroperitoneal tumors display higher local invasion and metastasis, generally cannot be completely excised. Therfore, they tend to have a poorer prognosis.
- (+)SMA, (+)Desmin
What is the most common type soft tissue sarcoma in children?
Rhabdomyosarcoma
In what anatomical locations can rhabdomyosarcoma generally be found?
- Bladder
- Head & neck
- Genitourinary tract
Usually found at locations with little to no skeletal muscle otherwise present
What are the three (3) major subtypes of rhabdomyosarcoma?
- Embryonal
- Alveolar
- Pleomorphic
What is sarcoma botyroides?
A variant of embryonal rhabdomyosarcoma that has the gross appearance of a ‘bunch of grapes’
What age group are embryonal rhabdomyosarcomas associated with? Alveolar rhabdomyosarcoma?
embryonal: < 10 years old
alveolar: 10-25 years old
What is the most common form of rhabdomyosarcoma?
Embryonal (49%)
Alveolar (31%)
What is(are) the gene(s) associated with alveolar rhabdomyosarcoma?
PAX3-FKHR (FOXO1)
PAX7-FKHR
What immunohistological findings are generally found with embryonal rhabdomyosarcoma?
(+)Desmin
(+)Myogenin, MyoD1
Where (anatomically) is alveolar RMS most frequently found?
Deep soft tissues of the extremities
Less common in: H&N, perineum, pelvis, retroperitoneum
Where (anatomically) is embryonal RMS generally found?
H&N, orbit and para-meninges
genitourinary tract
deep soft tissues of the extremities, pelvis, and retroperitoneum
In what patient population is synovial sarcoma most common?
young adults, primarily males
What is the most common anatomical location of synovial sarcoma?
Knee
Over 80% found in deep soft tissue of the extremities
What is the characteristic (90%) genetic association of synovial sarcoma?
t(X;18)(p11,q11)
Are the cells of synovial sarcoma derived from the synovium?
No
Its histogenesis is largely unknown
Synovial sarcoma
- Treatment
- common sites of metastasis
- Typical prognosis
- Aggressive limb-sparing excision (surgery)
- Common metastasis: lung, bone, regional lymph nodes
- Generally poor prognosis: 5yr 25-62%, 10yr 10-30%
