Soft Tissue Tumors (Rao)

Question 1

Approximately what percentage of all soft tissue tumors are sarcomas/

Answer 1

~1%

Benign tumors, mostly lipomas and hemangiomas, outnumber sarcomas by 100:1

Question 2

What is the most common etiology of soft tissue tumors?

Answer 2

Unknown (idiopathic) or sporadic

Question 3

Name (4) genetic syndromes associated with soft tissue tumors

Answer 3

1. Neurofibromatosis type 1 (neurofibroma, malignant schwannoma)
2. Gardner syndrome (fibromatosis)
3. Li-Fraumeni syndrom (soft tissue sarcomas)
4. Osler-Weber-Rendu syndrome (telangiectasia)

Question 4

Rhabdomyosarcoma chiefly affects what patient population?

Answer 4

children

Question 5

Synovial sarcoma tends to appear in what age group?

Answer 5

Young adults

Question 6

Grading of a soft tissue tumor is primarily based on what criteria?

Answer 6

1. Degree of differentiation/pleomorphism
2. Average number of mitoses per high-power field
3. Extent of necrosis

Question 7

Tumors arising in which of the following locations is generally associated with a better prognosis?

• Superficial locations
• Deep lesions

Answer 7

Superficial locations

Question 8

The presence of multiple lipomas is suggestive of what?

Answer 8

rare hereditary syndromes

Question 9

What is the most common type of soft tumor found in adults?

Answer 9

Lipoma

Question 10

True/False: complete excision of a lipoma is usually curative

Answer 10

True

Question 11

Classify the following types of liposarcoma based on degree of aggressiveness

1. Myxoid/round
2. Well-differentiated liposarcoma (WD-LPS)
3. Pleomorphic

Answer 11

1. Myxoid/round - usually intermediate aggressiveness
2. WD-LPS - Relatively indolent
3. Pleomorphic - usually aggressive and may metastasize

Question 12

At what anatomical locations are liposarcomas usually found?

Answer 12

Deep soft tissues of proximal extremities

Retroperitoneum

Question 13

Identify:

• a reactive non-neoplastic lesion that develops in response to trauma (or idiopathic). Develops suddenly and grows rapidly.

Answer 13

Pseudosarcomatous proliferation

**often mistaken for sarcoma

Question 14

Identify: A pseudosarcomatous proliferation that occurs in the deep dermis, subcutis, or muscle. Several centimeters in diameter with poorly defined margins.

Answer 14

Nodular fasciitis

Question 15

What is myositis ossificans?

Answer 15

• 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)

Question 16

What is a desmoid tumor?

Answer 16

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

Question 17

What is the most common age range for desmoid tumors?

Answer 17

teens to age 30

Question 18

Desmoid tumors are occasionally associated with what genetic syndrome(s)?

Answer 18

Gardner syndrome

Also associated with mutations in APC or ß-Catenin genes

Question 19

A superficial fibromatosis of occurring on the penis is called what?

Answer 19

Peyronie disease

Question 20

A superificial fibromatosis of the palmar surface of the hand is called what?

Answer 20

Dupuytren contracture

Question 21

Describe the general properties of a fibrosarcoma

Answer 21

• 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

Question 22

Name the disease associated with the following immunohistological marker(s):

• (+) vimentin
• all others negative

Answer 22

Fibrosarcoma

Question 23

What is the most common neoplasm found in women?

Answer 23

Uterine leiomyoma

Question 24

What type of sarcoma exhibits the following immunohistological markers?

• (+)SMA
• (+)Desmin

Answer 24

Leiomyosarcoma

Question 25

Describe the properties of Leiomyosarcoma, including: * major patient population * common anatomic location(s) * prognosis * immunohistochemical staining

Answer 25

* 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

Question 26

What is the most common type soft tissue sarcoma in children?

Answer 26

Rhabdomyosarcoma

Question 27

In what anatomical locations can rhabdomyosarcoma generally be found?

Answer 27

* **Bladder** * Head & neck * Genitourinary tract Usually found at locations with little to no skeletal muscle otherwise present

Question 28

What are the three (3) major subtypes of **rhabdomyosarcoma**?

Answer 28

1. Embryonal 2. Alveolar 3. Pleomorphic

Question 29

What is **sarcoma botyroides**?

Answer 29

A variant of embryonal rhabdomyosarcoma that has the gross appearance of a 'bunch of grapes'

Question 30

What age group are embryonal rhabdomyosarcomas associated with? Alveolar rhabdomyosarcoma?

Answer 30

embryonal: \< 10 years old alveolar: 10-25 years old

Question 31

What is the most common form of rhabdomyosarcoma?

Answer 31

Embryonal (49%) Alveolar (31%)

Question 32

What is(are) the gene(s) associated with alveolar rhabdomyosarcoma?

Answer 32

PAX3-FKHR (FOXO1) PAX7-FKHR

Question 33

What immunohistological findings are generally found with embryonal rhabdomyosarcoma?

Answer 33

(+)Desmin (+)Myogenin, MyoD1

Question 34

Where (anatomically) is alveolar RMS most frequently found?

Answer 34

Deep soft tissues of the extremities Less common in: H&N, perineum, pelvis, retroperitoneum

Question 35

Where (anatomically) is embryonal RMS generally found?

Answer 35

H&N, orbit and para-meninges genitourinary tract deep soft tissues of the extremities, pelvis, and retroperitoneum

Question 36

In what patient population is **synovial sarcoma** most common?

Answer 36

young adults, primarily males

Question 37

What is the most common anatomical location of **synovial sarcoma**?

Answer 37

Knee Over 80% found in deep soft tissue of the extremities

Question 38

What is the characteristic (90%) genetic association of **synovial sarcoma**?

Answer 38

t(X;18)(p11,q11)

Question 39

Are the cells of synovial sarcoma derived from the synovium?

Answer 39

No Its histogenesis is largely unknown

Question 40

Synovial sarcoma 1. Treatment 2. common sites of metastasis 3. Typical prognosis

Answer 40

1. Aggressive limb-sparing excision (surgery) 2. Common metastasis: lung, bone, regional lymph nodes 3. Generally poor prognosis: 5yr 25-62%, 10yr 10-30%