090514 soft tissue tumors

Question 1

soft tissue tumors

Answer 1

non epithelial extraskeletal tumors (excludes reticuloendothelial system, glia, and supporting tissue of parenchymal organs)

Question 2

benign soft tissue tumors outnumber sarcomas by what ratio

Answer 2

100/1

Question 3

causes of most soft tissue tumors

Answer 3

unknown

Question 4

where do 40 percent of soft tissue sarcomas occur

Answer 4

in the lower extremities, especially thigh

Question 5

compared to other sarcomas, what is the percentage of soft tissue sarcomas that occur in children?

Answer 5

15%, which is higher than for other sarcomas

Question 6

rhabdoymyosarcomas tend to occur at what age

Answer 6

childhood

Question 7

synovial sarcomas tend to occur at what age

Answer 7

young adulthood

Question 8

liposarcomas and pleomorphic or undifferentiated sarcomas tend to occur at what age

Answer 8

later adult life

Question 9

what ancillary techniques are there for prognosis of soft tissue sarcomas

Answer 9

immunohistochemistry
electron microscopy (less used now)
cytogenetics
molecular genetics

also, the grade of the tumor, size, depth, stage

Question 10

what contributes significantly to establishing prognosis for soft tissue sarcoma

Answer 10

accurate histologic classification (cell morphology, architectural arrangement)

these features may not be enough to distinguish however one sarcoma from another

Question 11

how are soft tissue sarcomas usually treated

Answer 11

with wide surgical excision (frequently limb-sparing)

for large high grade tumors, use irradiation and systemic therapy

Question 12

what is the most common soft tissue tumor of adulthood

Answer 12

lipoma

Question 13

how many lesions do you usually get with lipomas?

Answer 13

usually just one; multiple lipomas suggest rare hereditary syndromes

Question 14

characterization of most lipomas

Answer 14

painless (unless it’s an angiolipoma)
mobile
slowly enlarging

Question 15

what do lipomas look like histologically

Answer 15

lots of adipocytes

in some subclassifications:
in angiolipoma-blood vessels present
in spindle cell lipoma-spindle cells in it

Question 16

liposarcomas usually develop from

Answer 16

deep soft tissues of proximal extremities and retroperitoneum

Question 17

what types of liposarcomas are there

Answer 17

well differentiated
myxoid/round cell (intermediate grade)
pleomorphic histological variants

Question 18

well differentiated liposarcoma looks like histologically

Answer 18

there’s adipocytes like lipoma
however, there’s lipoblasts (not good-these are smaller than adipocytes; vacuolated bubbles in the cytoplasm; the nucleu is not at the periphery but at the center)

Question 19

what defines mixoid liposarcoma histologically?

Answer 19

adipocytes
mixoid stroma rich
slender vascular channels

Question 20

what does pleiomorphic liposarcoma look like histologically

Answer 20

cells don’t look like adipocytes
darker nuclei
less cytoplasm
may have stroma or slender channels

Question 21

what are pseudosarcomatous proliferations

Answer 21

non-neoplastic lesions that develop in response to local trauma or are idiopathic

develop suddenly, grow rapidly

hypercellularity, mitotic activity, and primitive apperance mimic sarcoma

Question 22

ex of psuedosarcomatous proliferations

Answer 22

nodular fasciitis

myositis ossificans

Question 23

nodular fasciitis

Answer 23

deep dermis, or muscle

several cm with poorly defined margins

histology: spindle cells, RBCs

Question 24

myositis ossificans

Answer 24

BONE within muscle
in proximal extremities, young adults, trauma (more than 50% of cases)

must be differentiated from extraskeletal osteosarcoma (if you look at imaging of myositis ossificans, will show that it is well circumscribed)

Question 25

fibromatoses

Answer 25

intermediate btwn fibroma and fibrosarcoma

superficial type and deep-seated (desmoid) type

superficial ones may stabilize and resolve, or recur

deep ones frequently recur after incomplete excision and are frequent in the teens to 30s; some associated with Gardner syndrome

Question 26

fibrosarcoma

Answer 26

malignant tumors composed of fibroblasts

mostly in adults

deep tissues of thigh, knee, retroperitoneum

Question 27

uterine leiomyomas

Answer 27

fibroids

Question 28

most common neoplasm in women

Answer 28

uterine leiomyomas

Question 29

smooth muscle tumors

Answer 29

uterus, skin, deep soft tissues

solitary lesions are easily cured

Question 30

leiomyosarcoma

Answer 30

more common in females than males

10-20% of soft tissue sarcomas

skin and deep soft tissues of extremities and retroperitoneum

Question 31

rhabdomyosarcoma

Answer 31

most common soft tissue sarcoma of childhood and adolescence

commonly in head, neck, or GU tract (usually at places where there is little if any normal skeletal muscle)

Question 32

3 subtypes of rhabdomyosarcoma

Answer 32

embryonal
alveolar
pleomorphic

Question 33

embryonal rhabdomyosarcoma histology

Answer 33

cells are small, round, and blue (dark nuclei)

not very often seen - but help with diagnosis- if you see elongated cells, which are rhabdomyoblasts

Question 34

diff btwn alveolar rhabdomyosarcoma and embryonal?

Answer 34

alveolar occurs in deep soft tissues of the extremities but less commonly in head and neck and perineum and retroperitoneum

Question 35

histology of alveolar RMS

Answer 35

small, round cells but arrnaged with large spaces like an alveolar pattern

Question 36

synovial sarcoma

Answer 36

of unknown origin in terms of cell origin

over 80% occurs in the deep soft tissue of extremities, especially knee

histology: biphasic (spindle and gland like cells) or monohpasic (one type of cell)

usually, translocation of DNA from chromosome X to 18