090514 soft tissue tumors Flashcards
soft tissue tumors
non epithelial extraskeletal tumors (excludes reticuloendothelial system, glia, and supporting tissue of parenchymal organs)
benign soft tissue tumors outnumber sarcomas by what ratio
100/1
causes of most soft tissue tumors
unknown
where do 40 percent of soft tissue sarcomas occur
in the lower extremities, especially thigh
compared to other sarcomas, what is the percentage of soft tissue sarcomas that occur in children?
15%, which is higher than for other sarcomas
rhabdoymyosarcomas tend to occur at what age
childhood
synovial sarcomas tend to occur at what age
young adulthood
liposarcomas and pleomorphic or undifferentiated sarcomas tend to occur at what age
later adult life
what ancillary techniques are there for prognosis of soft tissue sarcomas
immunohistochemistry
electron microscopy (less used now)
cytogenetics
molecular genetics
also, the grade of the tumor, size, depth, stage
what contributes significantly to establishing prognosis for soft tissue sarcoma
accurate histologic classification (cell morphology, architectural arrangement)
these features may not be enough to distinguish however one sarcoma from another
how are soft tissue sarcomas usually treated
with wide surgical excision (frequently limb-sparing)
for large high grade tumors, use irradiation and systemic therapy
what is the most common soft tissue tumor of adulthood
lipoma
how many lesions do you usually get with lipomas?
usually just one; multiple lipomas suggest rare hereditary syndromes
characterization of most lipomas
painless (unless it’s an angiolipoma)
mobile
slowly enlarging
what do lipomas look like histologically
lots of adipocytes
in some subclassifications:
in angiolipoma-blood vessels present
in spindle cell lipoma-spindle cells in it
liposarcomas usually develop from
deep soft tissues of proximal extremities and retroperitoneum
what types of liposarcomas are there
well differentiated
myxoid/round cell (intermediate grade)
pleomorphic histological variants
well differentiated liposarcoma looks like histologically
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)
what defines mixoid liposarcoma histologically?
adipocytes
mixoid stroma rich
slender vascular channels
what does pleiomorphic liposarcoma look like histologically
cells don’t look like adipocytes
darker nuclei
less cytoplasm
may have stroma or slender channels
what are pseudosarcomatous proliferations
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
ex of psuedosarcomatous proliferations
nodular fasciitis
myositis ossificans
nodular fasciitis
deep dermis, or muscle
several cm with poorly defined margins
histology: spindle cells, RBCs
myositis ossificans
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)
fibromatoses
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
fibrosarcoma
malignant tumors composed of fibroblasts
mostly in adults
deep tissues of thigh, knee, retroperitoneum
uterine leiomyomas
fibroids
most common neoplasm in women
uterine leiomyomas
smooth muscle tumors
uterus, skin, deep soft tissues
solitary lesions are easily cured
leiomyosarcoma
more common in females than males
10-20% of soft tissue sarcomas
skin and deep soft tissues of extremities and retroperitoneum
rhabdomyosarcoma
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)
3 subtypes of rhabdomyosarcoma
embryonal
alveolar
pleomorphic
embryonal rhabdomyosarcoma histology
cells are small, round, and blue (dark nuclei)
not very often seen - but help with diagnosis- if you see elongated cells, which are rhabdomyoblasts
diff btwn alveolar rhabdomyosarcoma and embryonal?
alveolar occurs in deep soft tissues of the extremities but less commonly in head and neck and perineum and retroperitoneum
histology of alveolar RMS
small, round cells but arrnaged with large spaces like an alveolar pattern
synovial sarcoma
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
