soft tissue tumor

Question 1

Embryonic mesoderm gives rise to

Answer 1

Skeletal system, muscular system (smooth and skeletal), dermis and connective tissue, hematopoietic system, reproductive system, pleura, peritoneum, adrenal cortex

Question 2

Soft tissue (mesenchymal) tumors = non-epithelial extraskeletaltumors •excluding reticuloendothelialsystem, glia, and supporting tissue of parenchymal organs

Answer 2

incidence is RARE of soft tissue tumors

mostly is lipomas and hemangiomas

Question 3

Pathogenesis of soft tissue tumor

Answer 3

majority of soft tissue tumors occur sporadically, but minority are associated with genetic syndromes

NeuroFibromatosis type 1 (Malignant peripheral nerve sheath tumor--NF1)
Gardner syndrome (fibromatosis) APC
Lifraumeni syndrome (soft tissue sarcomas), P53
Hereditary hemorrhagic telangiectasia (many genes) 

The cause of most soft tissue tumors unknown (many times following radiation therapy, rare instances following chemical burns, thermal burns, trauma)

incidence of sarcomas increase with age

Rhabdomyosarcoma (childhood), Synovial sarcoma (young aduldhood), liposarcoma and pleomorphic sarcomas in later adult

Question 4

Anatomic Distribution of sarcomas and treatment

Answer 4

Happen any where
60% occur in extremities, 40% in lower extremites (especially in the thigh)

treatmrent wide excision, radiation and chemo for large and high grade tumors

Question 5

Lipoma

Answer 5

most common soft tissue tumor of adulthood, benign, most solitary lesions (multiple lipomas–> hereditary syndrome)

Most are mobile slowly enlarging, painless masses (angiolipomas can manifest with local pain)

Complete excision usually is curative

conventional lipomas are soft, yellow well encapsulated masses

On exam histo: white fat cells with no pleomorphism
12 q 13 14

Question 6

liposarcoma

Answer 6

one of the most common sarcomas of adulthood

Deep soft tissues of proximal extremities and retroperitoneum, may develop into large tumors

Well differentiated, myxoid/round cell, and pleomorphic histological variants

youll see lipoblasts, will all recur if not excised adequately

Well differentiated indolent (MDM2 w/ supernemery ring)
Myxoid is intermediate (t 12 16, Fos chop)
Pleomorphic variant aggressice and metastasizes

Lipoblastoma: kids (PLAG1), hibernoma (kids brown fat

Question 7

Fibromatoses

Answer 7

Superficial: Palmar (dupuytren contracture), plantar, penile (peyronie disease) may stabilize and resolve spontaneously

Deep seated fibromatosis (Desmoid tumors), behavior lies between benign fibrous tumors and low grade fibrosarcomas, frequently recur after incomplete excision, most frequent in teen to 30s, Gardners syndrome, APC, B catenin

Question 8

Fibrosarcoma

Answer 8

malignant tumors composed of fibroblasts

Mostly adults
Deep tissues of the thigh, knee, and retroperitoneum

Aggressive tumors (recur in 50% of cases), metastasize in 25%

Question 9

Leiomyoma

Answer 9

Smooth muscle tumors

Uterine leiomyomas (most common neoplasm in women)
May also arise in the skin and deep soft tissues
Usually less than 1-2 cm

Solitary lesions easily cured

Multiple tumors may be difficult to remove

10-20% of soft tissue sarcomas, adults, skin deep soft tissue of the extremities and retroperitoneum, superficial leiomyosarcomas usually small and have good prognosis

Those in retroperitoneum are large, cannot be entirely excised (local extension adn metastatic spread)

Question 10

Rhabdomyosarcoma

Answer 10

most common soft tissue sarcoma of childhood and adolescence usually less than 20 yo

Most common in head, neck or GUT

Subtypes: embryonal, alveolar, pleomorphic

Question 11

Embryonal Rhabdomyosarcoma

Answer 11

49% of RMSs
more frequent less 10 yrs of age
(head and neck in particular orbital and parameningeal, GUT, deep soft tissues of the extremities, pelvis and retroperitoneum

Variant: sarcoma botryoides, spindle cell, anaplastic

ERMS often has loss of 11p15 and extra copies 8 12 13 and 20

Botryoid: often infant girls with protruberent vaginal lesions also GU and head and neck
Polypod, gelatinous mass with a bunch of grapes appearance, Often has cambium layer of tumor cells underlying the native epithelium

Question 12

alveolar rms

Answer 12

31 % of RMSs
More frequent in 10-25s
Deep soft tissues of the extremities, less frequently in (head and neck, perineum, pelvis, retroperitoneum)

Pathognomonic translocations (t213 Pax3fox01, t1 13 pax7 foxo1

Question 13

Synovial sarcoma

Answer 13

5-10% of all soft tissue sarcomas
Young adults, more commonly males
Over 80% in deep soft tissue of extremities around knee
Histologically biphasic, monophasic

T x 18 p 11 11 with syt SSX1 or SYT sSx2

Treated aggressively with limb sparing surgery and chemotherapy, common metastatic sites are lung, bone, and regional lymph nodes

5 year survival rates range from 25-60%
Only a quarter live more than 10 years :(

Question 14

Pseudosarcomatous proliferations

Answer 14

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, primitive appearance mimic sarcoma

Nodular fascilitis (self limited, transient neoplasia, deep dermis, SubQ, muscle, several centimeters with poorly defined margins)

t 17 22 translocation

Myositis ossificans: proximal extremities, young adults, presense of metaplastic bone, eventually entire lesion ossifies, must be distinguished from extraskeletal osteosarcoma