Soft Tissue Tumors Flashcards
diagnostic features of sarcomas
cell morphology/cytology, architectural arrangement
ancillary techniques
new: cytogenetics, molecular genetics. older: immunohistochemistry, electron microscopy
lipoma
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
lipoma histology
conventional lipomas are soft, yellow, well-encapsulated masses
histologically, they consist of mature white fat cells with no pleomorphism
conventional lipomas: 12q14-q15
liposarcoma
one of the most common sarcomas of adulthood
well-differentiated, mixiid/round cell, and pleomorphic histological variants
liposarcoma histology
lipoblasts are small vacuolated bubbles, central and indented nucleus =bad news!
liposarcoma behavior
WD-LPS-relatively indolent
myxoid/round cell type=intermediate
pleomorphic=usually aggressive and may metastasize
all types recur locally unless adequately excised
pseudosarcomatus proliferations
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
examples of pseudosarcomatus proliferations
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)
superficial fibromatoses
palmar (Dupuytren contracture), plantar, penile (Peyronie disease)
may stabilize and resolve spontaneously; some recur
deep-seated fibromatosis (desmoid tumors)
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
fibrosarcoma
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
most common neoplasm in women
uterine leiomyomas
smooth muscle tumors
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
leiomyosarcoma
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)
rhabdomyosarcoma
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
subtypes of rhabdomyosarcomas
embryonal
alveolar
pleomorphic
embryonal rms
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
embryonal rms histology
cells are mostly small and very dark, purple nuclei
rhabdomyoblast-elongated cytoplasm; diagnostic, but hard to see usually
positive staining for desmin and myogenin
alveolar rms
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
alveolar rms chromosomal transolcation
t(2; 13)/PAX3-FKHR or t(1; 13)/PAX7-FKHR are present in most (80-85%) cases of alveolar RMS
tumors of unknown histiogenesis
synovial sarcoma
epithelia sarcoma
alveolar soft part sarcoma
others
synovial sarcoma
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
synovial sarcoma treatment, mets sites, and prognosis
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
