soft tissues Flashcards
General principles
benign outnumber malignant at least 100:1
metastasis tend to be “blood born” to lungs, liver, bone
40% lower extremity; especially thigh
30% trunk and retroperitoneum
bone involved by direct extension or metastasis
Etiology
most common cause is unkown
associations: radiation, trauma (post massectomy: angiosarcoma, HHV8 (kapsi’s sarcoma), chemical exposure, and thermal burns
Genetic syndromes
neurofibromatosis types 1: malignant peripheral nerve sheath tumor
gardner syndrome: fibromatosis (desmoid)
li-fraumeni syndrome (mutant p53): osft tissue sarcoma and other malignancies
hereditary hemorrhagic telangiectasia (osler-weber-rendu disease): teleangiectasias over skin and mucosal surfaces
Ewing sarcoma and primitive neuroectodermal tumor
t (11:22) (q24;q12) EWS FLI1 fusion
liposarcoma myxoid and round cell type
t(12:16)(p13;q11) FUS-DDIT3 fusion
Synovial sarcoma
t(x;18)(p11;q11) SS18-SSX fusion gene
rhabdomyosarcoma alveolar type
t(2;13)(q35;q14) PAX3-FOX01 fusion
extraskeletal myxoid chondrosarcoma
t(9;22)(q22;q12) EWS-CHN fusion
Age: What is most common for each age group
15% arise in children
rhabdomyosarcoma in children
synovial sarcoma in young adults
undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma) and liposarcoma in mid to late adulthood.
What affects Prognosis
Type (recapitulation of tissue type)
stage (location and size): superficial vs deep, size, metastasis, etc
grade: cell pleomorphism, necrosis, mitotic
Cell type: Spindle cell
rod shaped, long axxis at least twice short axis
fibrous, schwann cell, firbohistocytic, smooth msulce
Cell type: small round (blue) cell
round, little cytoplasm
rhabdomyosarcoma, PNET/EWINgs
Cell type: epitheliod
polyhederal; more cytoplasm
epithelioid sarcoma
Cell type: matrix producing
bone, cartilage
extrasekeletal osteosarcoma
Cell type: biphasic
spindle and epithelial cells
biphasic synovial sarcoma
architectural patterns: fascicles of spindle cells
smooth muscle
architectural patterns: short fasciles of spindle cells radiating from center (storiform; pinwheel-like)
fibrohistiocytic
architectural patterns: nuclei in columns (palisading)
schwann cell
architectural patterns: herringbone
fibrosarcoma
architectural patterns: biphasic: spindle and epithelioid
synovial sarcoma
lipoma: description, location, and convention
most common adult soft tissue tumor: soft, mobile. Painless with one exception (angiolipoma)
most common location: subcutaneous trunk and proximal extremities
conventional: thinly encapsulated yellow tumor. Lobules of mature fat
other lipoma variaants
fibrolipoma: fibrous areas
angiolipoma: small vessels
dpinle cell lipoma: spindle cell areas
intramusclular lipoma: lipoma within muscle
liposarcoma age, location, and types (4)
adults 40-60
deep soft tissues: retroperitoneum (often very large). Proximal extremities
types: well differentiated (retroperitoneal), myxoid/round cell (extremities), pleomorphic-very aggressive course, dedifferentiated
liposarcoma, well differentiated: overview, gross, histo, growth description, genetics
most common type of liposarcoma
gross appearance same as lipoma
micro can be very close to benign lipoma: atypical spindle cells. Lipoblast: cytopalsmic vacuoles scallop nucleus
tend to be indolent with local recurrence
MDM2 amplification (inhibits p53)
liposarcoma, myxoid/round cell: genetic, location, histo
t(12;16) FUS-DDiT3 fusion protein
intramuscular, most often the thigh
round cell component is aggressive: rare lipoblast
myxoid tends to be indolent: chicken wire pattern of thin capillaries, rare lipoblast
Liposarcoma, others
pleomorphic liposarcoma: very aggressive
dedifferentiated liposarcoma: sarcoma arising from a well differentiated liposarcoma
Fibrous (myofibroblastic) tumors/proliferations Types
benign reactive proliferations: nodular fasciitis, myositis ossificans
fibromatoses: deep fibromatosis (desmoid), superficial fibromatosis
fibroma
fibrosarcoma
nodular fasciitis: location, growth description
most common on volvar forearm
solitary rapidly growing 2-3 cm: may be painful. 10% history of trauma
deep dermis, subcutis, or muscle
reactive process, rarely recurs if excised
spindle cell proliferation of fibroblasts
Myositis/panniculitis ossificans: age, cause, location, differentatiation
atheltetic adolescents and young adults
50% trauma
subcutaneous and muslce
early painful, circumscribed and firm
3-6 cm
fibroblastic but later develops bone
ends as trabecular bone with marrow
fibromatoses types
superficial fibromatosis: palmer fibromatosis, plantar fibromatosis, penile fibromatosis
deep seated fibromatosis (desmoid tumor): extra abdominal, abdominal, intra abdominal
superficial fibromatosis: histo, differentiation,
nodular or poorly defined fascicles of fibroblasts and abundant collagen
course: may progress, regress or stabilize
may recur after excision
Palmer fibromatosis (dupuytren’s contracture)
nodular thickening of palmer fascia; puckers skin and digit flexion contraction (mostly 4 and 5)
50% bilateral
Plantar fibromatosis
bilateral infrequent
irregular of nodular thickening of plantar fascia
penile fibromatosis (peyronie’s disease)
induration of mass on dorsolateral penis
can cause abnormal curvature of penis
can constrict urethra
deep-seated fibromatosis (desmoid tumors)
large infiltrative: locally aggressive, but does not metastasize
teens-30s
mutation in APC or b-catenin
recur if not completely excised: wide margin needed
deep seated fibromatosis types
abdominal: anterior abdominal wall, women during or after preganncy or c section.
intra abdominal desmoid: mesentry and pelvic walls, gardner syndrome
extra abdominal
gray white poorly demarcated
fibroiblasts in fascicles infiltrate tissue
fibrosarcoma
rare; most common in deep extremities
infiltrative fish-flesh with hemorrhage and necrosis
spindle cell with areas of herringbone pattern
50% recur, 25% metastasize
skeletal muscle tumors: types
rhabdomyoma
cardiac rhabdomyoma
rhabdomyosarcoma: embryonal, alveolar, pleomorphic
rhabdmyosarcoma: age, location on body
most common soft tissue sarcoma of childhood and adolescence; rare after age 20
head/neck (nasal cavity, orbit, middle ear)
gu tract
embryonal rhabdomyosarcoma: age and subtypes
60% of rhabdomyosarcomas
chidlren < 10 years
subtypes: sarcoma botryoides in walls of hollow viscera and mucosal lined structures
embryonal rhabdomyosarcoma: histo
soft gray infiltrative mass
mimic skeletal muscle embryogenesis: round and spindle cells
sarcoma botryoides variant: cluster of grapes protrude into lumen. Cambium layer: submucosal hypercellular area, best prognosis amongst embryonal rhabdomyosarcoma
rhabdmyosarcoma: rhabdomyoblast
eccentric eosinophilic cytoplasm with thick and thin filaments
tadpole cells and strap cells
EM: sarcomeres
myogenic markers positive: MYOD1, myogenin, desmin
small round blue cell
may see cross striations in some cells
alveolar rhabdmyosarcoma: age, location in body, histo, genetic, prognosis
early to mid adolescence
deep muscles of extremities
fibrous septa divide tumor into alveolar-like spaces centrally containg discohesive cells while peripheral cells stick to wall
t(2;13) or t (1;13): PAX3 or PAX7 to FOXO1
poor prognosis vs embryonal
pelomorphic rhabdmyosarcoma: location in body, histology, caveats
deep soft tissue of adults
very pleomorphic with rhabdomyoblasts
often mistaken for undifferentiated pelomorphic sarcoma: desmin positive, myod1 or myogenin positive
rhabdmyosarcoma prognosis ranking
sarcoma botryoides: best
embroyonal: second best
alveolar and pleomorphic: poor
65% of children are cured
adults do poorly
Leiomyoma: description, location,
benign smooth muscle tumor
most common in uterus
skin: erector pili, niipples, scrotum, labia. Pilar leiomyoma often painful and multiple. Adolescent and early adults.
bland smooth muscle cells in fascicles
rare in deep tissues
Leiomyosarcoma: gender, description histo, tests
10-20% of soft tissue sarcomas
F>M
skin, deep extremities and retroperitoneum
white masses can be large
malignant spindle cells
smooth muscle actin and desmin
negative for MyoD1 and myogenin
synovial sarcoma: age, location in body and histo. genetics
originally believed to recaptiulate synovium but cell of origin is unknown: <10% intra articular
10% of soft tissue sarcomas
age 20-40
deep and around large joints: 60-70% lower extremities, especially knee/thigh. often microcalcifications on xray
t(x;18) SYT-SSX1 or SYT-SSX2 fusion
prognosis: 25-60% 5 years
synovial sarcoma:
biphasic (dual) differentiation: epithelial cells as glands, cords, or nests. SPindle cells: cellular in fascilces
monophasic (spindle cell) variant: positive for cytokeratins (epithelial marker), epithelial membrane antigen (EMA)
undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma): description, pattern, location, histo
group of aggressive neoplasms
cell pleomorphism and storiform pattern (diagnosis of exclusion)
proximal extremities and retroperitoneum
large grey, hemorrhagic and or necrotic
metastasis 30-50%
immunohistochemistry: epithelial membrane antigen and cytokeratin
general epithelial marker
immunohistochemistry: MyoD1 and myogenin
skeletal muscle
immunohistochemistry: actin and desmin
skeletal or smooth muscle
immunohistochemistry: vimentin
nonepithelial tumors
immunohistochemistry: smooth muscle actin
smooth muscle
immunohistochemistry: Epithelium
cytokeratin and EMA
immunohistochemistry: skeletal muscle
myoD1, myogenin, desmin and actin
immunohistochemistry: smooth muscle:
desmin and actin
immunohistochemistry: nonepithelial tumors
vimentin
painful skin lesions “blue angel”
blue rubber bleb nevus
angiolipoma
neuroma (traumatic)
glomus tumor
eccrine spiradenoma
leiomyoma (cutaneous)
