Soft Tissue Tumors Flashcards
where are the dermis and connective tissue derived from?
mesoderm
where is the muscular system (smooth and skeletal) derived from?
mesoderm
What are mesnechymal (soft tissue) tumor? How are they calssified?
- nonepithelial extraskeletal tumors (excluding reticuloendothelial system, glia, and supporting tissue of parenchymal organs)
- classified according to the tissue they recapitulate (muscle, fat, fibrous tissue, vessel or nerves) the tissue they are trying to be
- benign soft tissues=oma
- malignant soft tissue tumors=sarcomas
what percentage of cancers are sarcomas?
1%
benign outnumbers sarcomas by 100:1
How do soft tissue tumors occur?
- a majority of soft tissue tumors occur sporadically, but an important minority are associated with genetic syndromes
- ex: Neurofibroms (NF1-malignant peripheral nerve sheath tumor), Garder Syndrome (fibromatosis) APC, Li Fraumen syndrome (soft tissue sarcomas) p53, hereditary hemorrhagic telangiectasia- multiple genes
- cause of most is unknown
How does the incidence of sarcomas relate to age?
incidence increases with age. 15% arise in children
- Rhabdomyosarcomas in childhood
- synovial sarcoma in young adulthood
- liposarcoma and pleomorphic or undifferentiated sarcomas in later adutl life
Where do sarcomas occur?
any location! 60% in extremities, with 40% being in lower extremities (especially thighs)
Accurate histologic classification contributes significantly to establishing the prognosis of a sarcoma. what are 2 important diagnostic features?
- cell morphology and architectural arrangement
- ancilalary techniques help esp when the diagnostic features are hard to distinguish for example in a poorly differentiated tumor
- Immunohistochemistry
- electron microscopy
- cytogenetics
- molecular genetics
What predicts the behavior of a soft tissue sarcoma? What are a few other afctors that distinguish prognosis?
Grade!
I-III (low, medium, high)
- degree of differentiation/pleomorphism
- average nuber of mitoses per high-power field
- extent of necrosis (presumably a reflection of rate of growth)
size and depth and stage of tumor are also important in deciding prognosis (superficial is better prognosis than deep lesions)
How do we usually treat sarcomas?
soft-tissue sarcomas are usually treated with wide surgical excision (frequently limb sparring). radiation and chemotherapy are used for large and/or high grade tumors
WHere are lipoma, hibernoma, liposarcomas located?
adipose tissue
where are neurofibroma, schwannoma, perineuriroma, malignant peripheral nerve sheath tumor (MPNST) located
nerve
where are leiomyoma, leiosarcoma and rhabdomyoma, rhabdosarcoma located?
muscle lei=smooth, rhabdo=skeletal
where are hemangioma, hemangioendothelioma, angiosarcoma located?
blood vessle
WHat is the most common soft tumor of adulthood?
lipoma
tell me about lipomas? what is their growht like? how to you treat them?
- most common soft tissue tumor os adulthood
- benign solitary lesion (multiple lipomas suggest presence of rare hereditary syndrome)
- most are mobile, slowly emerging, painless masses ( angiolipomas can manifest wiht local pain)
- complete excision is curative
How are lipomas subclassed? what are typical lipomas like? what do you see on histological exam? What are the typical abberations?
- subclassified according to particular morphologic features (angiolipoma, spindle, cell lipoma)
- conventional lipomas are soft, yello, well-encapsulated masses
- on hitological exam they consist of mature white fat cells with no pleomorphism
- 12q14-q15
How common are liposarcomas? where do they occur? what are they like morphologically?
- one of most common sarcomas
- deep soft tissues of proximal extremities and retroperitoneum
- may develop int large tumors
- well-diffeentiated, myxoid/round cell, and pleomorphic histologica variant
How do liposarcomas behaive?
well-differentiated Liposarcomas (LPS) is relatively indolent
myxoid.round cell LPS is intermediate
pleomorphic variant usually aggressive and may metastasize
***alll types recur locally unless adequately excised***
What genetically speaking often leads to well-differerntiated liposarcomas?
supernumerary ring chromosomes (amplification of 12q14-q15, containing MDM2)
(remember MDM2 sequesters p53 so mor MDM2 means less p53 and less tumor suppression)
what geneticall yspeaking usually causes a myxoid/round LPS
t(12;16) (q13;p11) forms a FUS-CHOP fusion gene
Lipoblastoma- who gets them and what are they composed of?
children, primarily lipoblasts, PLAG1
Hibernoma-
children, bronw fat (vs. white fat in lipoma)
where do superficial fibromatosis occur?
- palmar (dupuytren contracture)
- plantar
- enile (peyronie disease)
- may stabilize and resolve spontaneously, though some recur
How do deep-seated fibromatosis (desmoid tumors) behaive? who gtes it?
- somewhere between benign fibrous tumors and low-grade fibrosarcomas
- frequently recur after incomplete excision
- usually teens to 30s
- some associated with gardner syndrome
- mutations in the APC of B-catenin genes
What are fibrosarcomas? who gets them? where do they occur? How do they behaive?
- malignant tumors composed of fibroblast
- mostly adults
- deep tissues of the thigh, knee, and retroperitoneum
- aggressive tumors
- recur in >50% of cases
- metastasize in ?25%
What are Leioyomas? Where do they often occur? what is their typical size? how are they treated
Leiomoya=benign smooth muscle tumor
- usually in the uterus but may also occur in skin and deep soft tissues
- usually <1-2cm
- treatment: solitary lesion easily cured, but multiple tumors may be difficult to remove
What are Leimyosarcomas? Who typically gets them? where do they occur? prognosis?
malignant smooth muscle tumors
- 10-20% of soft tissue sarcomas, occur in adults and in females over males
- occur in the skin and deep soft tissues of the extremities and retroperitoneum
- when superficial and small they have a good prognosis, but when in retroperitoneum and large the can’t easily be excised and local extension and metastatic spread occur
What is a Rhabdomyosarcoma? Where does it usally occur and what are the 3 subtypes?
- the most common soft tissue sarcoma of childhood and adolescence. usually under 20 yo
- most commonly in head and neck or genitourinary tract
- subtypes
- embryonal, alveolar, pleomorphic
Embryonal RMS
- what percentage of RMS’s are embryonal?
- what age group are they more frequent in?
- where do they typically occur?
- what are the variant?
- what is the common genetic lesion?
- 49% of RMS
- more frequent under 10 yo
- occurs in hollow sapces: head and neck (orbital and parameningeal), genitourinary tract, deep soft tissues of the extremities, pelvis and retroperitoneum
- variants are:
- sarcoma botryoides
- spindle cell
- anaplastic
- ERMS often has loss of 11p15 and extra copies of 8, 12, 13, and/or 20 (but no single cytogenic feature
WHat is a botryoid?
an embryonal RMS often in infant grils with protruberant vaginal lesions; also GU and head and neck
polypoid, gelatinous mass wiht a “bunch of graps” appearance
often has “cambium layer” of tumor cells underlying the native epithelium
What is MyoD1?
a marker of immature skeletal muscle
What do ERMS look like histologically?
dark and large nucleus. “strap cell” they are trying soooo hard to be a skeltal muscle cell but it just can’t get it right
What percentage of RMS are alveolar? what age is alveolar RMS common? where do they occur? What is the common cytogenetics that defines it?
- 31% of RMS
- More frequent between age 10 and 25
- occurs in
- deep soft tissues of the extremities
- leff frequently in head and neck, perineum, pelvis, retroperineum
- ARMS has pathognomic translocations
- t(2;13)/ FOXO1 (FKHR)
- t(1;13(/PAX7-FOXO1 (FKHR)
**named bc looks like alveoli histologically
synovial sarcoma incidence? location? what does ti look like histologically? translocation?
5-10% of all soft sarcomas, yong adults usualyl male
over 80% occur in deep soft tissue of extremities, especially around the knee
histologically biphasic or monophasic
cahracterized by cytogenetic change: t(x;18) (p11;q11) with SYT-SSX1 or SYT-SSX2
is this tissue monophasic or biphasic?
monophasic
is this tissue monophasic or biphasic?
biphasic
How does FISH work to identify synovial sarcoma?
the cytogenetic change si two geneti peices moving farther away from each other, so you mark each peice with red and green. if they stay righ tnext to each toher you see yello, but if they move you see red and green
How do you treat a synovial sarcoma?
aggressively with limb-sparing surgery and chemotherapy
common metastasis to lungs, bone, and regional lymph nodes
5 year survival range from 25%-60% only about a quarter of patients sruvive longer than 10 years
WHat translocation is assocaited with Ewing sarcoma/PNET?
t(11;22)(q24;q12)
What are pseudosarcomatous proliferations? why is is confused with sarcomas?
reactive non-neoplastic lesions that develop in repsonse to some form of local trauma or are idiopathic
develop suddenly and grow rapidly
hypercellularity, mittic activity and primitive appearance mimic a sarcoma
what is nodualr fasciitis? how is it treated? where does it occur? what is the translocation assocaited?
a pseudosarcomatous proliferation
- sel limited or transient neoplasia
- deep dermis, subcutis or muscle
- several cm with poorly defined margins
- MYH9-USP6 translocation from t(17;77)
**extravated red blood cells with tissue culture appearance
What is myositis ossificans? Where does it occur?
- proximal extremities, young adults, antecedent trauma in >50% of cases
- presence of metaplastic bone; eventually the entire lesion ossifies and the intertrabecular spaces become filled with boen marrow
- must be distinguished from extraskeletal osteosarcoma
most common benign soft tissue tumor ______
most common malignant adult soft tisue tumor ______
most common malignant pediatric soft tissue tumor ________
most common benign soft tissue tumor: lipoma
most common malignant adult soft tissue tumor: liposarcoma
most common malignant pediatric soft tissue tumor: rhabdomyosarcoma
how do you treat small, low grade tumors?
how about large, high grade?
small, low grade- surgical resection
large, high grade-surgical resection plus chemotherapy and radiation
What 3 things are often encorporated into the pathologic diagnostic process?
immunohistochemistry
radiology
electron microscopy
