Soft Tissue Tumors

Question 1

diagnostic features of sarcomas

Answer 1

cell morphology/cytology, architectural arrangement

Question 2

ancillary techniques

Answer 2

new: cytogenetics, molecular genetics. older: immunohistochemistry, electron microscopy

Question 3

lipoma

Answer 3

most common soft tissue tumor of adulthood; most are solitary lesions
multiple lipomas suggest lypomitoses
most are mobile, slowly enlarging, painless masses
complete excision is usually curative

Question 4

lipoma histology

Answer 4

conventional lipomas are soft, yellow, well-encapsulated masses
histologically, they consist of mature white fat cells with no pleomorphism
conventional lipomas: 12q14-q15

Question 5

liposarcoma

Answer 5

one of the most common sarcomas of adulthood

well-differentiated, mixiid/round cell, and pleomorphic histological variants

Question 6

liposarcoma histology

Answer 6

lipoblasts are small vacuolated bubbles, central and indented nucleus =bad news!

Question 7

liposarcoma behavior

Answer 7

WD-LPS-relatively indolent
myxoid/round cell type=intermediate
pleomorphic=usually aggressive and may metastasize
all types recur locally unless adequately excised

Question 8

pseudosarcomatus proliferations

Answer 8

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

Question 9

examples of pseudosarcomatus proliferations

Answer 9

nodular fasciitis (deep dermis, subcutis, or muscle; several cm’s with poorly defined margins; histology-extravasated RBCs is a classic finding of NF)

myositis ossificans (proximal extremities, young adults, trauma in >50% of cases; presence of metastatic bone-eventually the entire lesion ossifies and the intertrabecular spaces become filled with bone marrow; must be distinguished from extraskeletal osteosarcoma; histology-neat and well circumscribed margins)

Question 10

superficial fibromatoses

Answer 10

palmar (Dupuytren contracture), plantar, penile (Peyronie disease)
may stabilize and resolve spontaneously; some recur

Question 11

deep-seated fibromatosis (desmoid tumors)

Answer 11

behavior lies between benign fibrous tumors and low-grade fibrosarcomas
frequently recur after incomplete excision
most frequent in the teens to 30s
some associated with Gardner syndrome
mutations in the APC or B-catenin genes

Question 12

fibrosarcoma

Answer 12

malignant tumors composed of fibroblasts
mostly adults
deep tissues of the thigh, knee, and retroperitoneum
agressive tumors; recur in >50% of cases, metastasize in >25%
histology-all markers but vimentin are negative

Question 13

most common neoplasm in women

Answer 13

uterine leiomyomas

Question 14

smooth muscle tumors

Answer 14

most common in women=uterine leiomyomas
may also arise in the skin and deeps soft tissues
usually <1-2cm
solitary lesions easily cured
multiple tumors may be difficult to remove

Question 15

leiomyosarcoma

Answer 15

10-20% of soft-tissue sarcomas
adults, F>M
skin and deep sod tissues of the extremities and retroperitoneum
-superficial leiomyosarcomas usually small and have good prognosis
-those in the retroperitoneum are large, cannot be entire excised (local extension and metastatic spread)

Question 16

rhabdomyosarcoma

Answer 16

most common soft tissue sarcoma of childhood and adolescence, usually before the age of 20
most commonly in head and neck or genitourinary tract (particularly urinary bladder), usually at sites where there is little, if any, normal skeletal muscle

Question 17

subtypes of rhabdomyosarcomas

Answer 17

embryonal
alveolar
pleomorphic

Question 18

embryonal rms

Answer 18

49% of RMS
more frequent <10yrs
head and neck (particularly orbit and parameninges)
genitourinary tract
deep soft tissues of the extremities, pelvis, and retroperitoneum
variants: sarcoma botryoides, spindle cell, anaplastic

Question 19

embryonal rms histology

Answer 19

cells are mostly small and very dark, purple nuclei
rhabdomyoblast-elongated cytoplasm; diagnostic, but hard to see usually
positive staining for desmin and myogenin

Question 20

alveolar rms

Answer 20

31% of RMS
more frequent between 10 and 25 years of age
deep soft tissues of the extremities
LESS frequent in: head and neck, perineum, pelvis, retroperitoneum
histology: “alveolar” pattern

Question 21

alveolar rms chromosomal transolcation

Answer 21

t(2; 13)/PAX3-FKHR or t(1; 13)/PAX7-FKHR are present in most (80-85%) cases of alveolar RMS

Question 22

tumors of unknown histiogenesis

Answer 22

synovial sarcoma
epithelia sarcoma
alveolar soft part sarcoma
others

Question 23

synovial sarcoma

Answer 23

5-10% of all soft tissue sarcomas
young adults, M>F
over 80% in the deep soft tissue of the extremities, especially around the knew
characteristic t(X; 18)(p11;q11)
histologically biphasic or monophasis

Question 24

synovial sarcoma treatment, mets sites, and prognosis

Answer 24

treated aggressively with limb-sparing surgery and chemotherapy
common metastatic sites are lung, bone, and regional lymph nodes
5-year survival rates range from 25% to 62% and only 10-30% of patients live longer than 10 years