Dougherty Part 9 Flashcards
when and where does alveolar rhabdomyosarcoma present
early to mid-adolescence
deep muscle of extremities
what causes alveolar rhabdomyosarcoma?
t(2;13) or t(1;13)
PAX3 or PAX7 to FOXO1
what is seen in alveolar rhabdomyosarcoma
fibrous septa divide tumor into alveolar-like spaces centrally containing discohesive cells while peripheral cells stick to wall
pleomorphic rhabdomyosarcoma is presents where and when
deep soft tissue of adults
pleomorphic rhabdomyosarcoma is often mistaken for undifferentiated pleomorphic sarcoma. what differentiates the two
pleomorphic rhabdomyosarcoma is:
desmin positive
MyoD1 or myogenin positive
what are the different rhabdomyosarcoma prognosis’
best: sarcoma botryoides
second best: embryonal
poor: alveolar and pleomorphic
65% of children are cured
what is a leiomyoma
benign smooth muscle tumor
bland smooth muscle cells in fasicles
where is the most common site of a leimyoma
uterus
other than the uterus leiomyoma is found at what sites
skin: erector pili, nipples, scrotum, labia
pilar leiomyoma often painful and multiple
what is found in leiomyosarcoma and what tests is it negative for
smooth muscle actin and desmin
malignant spindle cells
negative for MyoD1 and myogenin
leiomyosarcoma can be found at what sites
skin, deep extremities, and retroperitoneum
synovial sarcoma is caused by what
t(X;18)
SS18-SSX fusion
synovial sarcoma is found in what age group and where
20-40s
deep and around large joints
60-70% lower extremities (KNEE/THIGH)
biphasic (dual) differentiation is what and seen in what
epithelial cells as glands, cords, or nests
spindle cells: cellular in fascicles
synovial sarcoma
what types of synovial sarcoma has what types
biphasic (dual) differentiation
monophasic (spindle cell) variant
what is seen in the monophonic (spindle cell) variant of synovial sarcoma
positive for cytokeratins (epithelial marker)
epithelial membrane antigen (EMA)
what are undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma)
group of aggressive neoplasms
found in proximal extremities and retroperitoneum
what is seen in undifferentiated pleomorphic sarcoma (malignant fibrous histiocytoma)
cell pleomorphism and storiform pattern (diagnosis of exclusion)
large grey, hemorrhagic and/or necrotic
what is in immunohistochemistry that is a marker of epithelium
epithelial membrane antigen
cytokeratin
what is in immunohistochemistry that is a marker of skeletal muscle
MyoD1 and Myogenin
Actin and Desmin
what is in immunohistochemistry that is a marker of smooth muscle
smooth muscle actin
Actin and Desmin
what is in immunohistochemistry that is a marker of a non epithelial tumor
vimentin
what is a myopathy
disorder of the muscles
what is muscular dystrophy
inherited disorder
progressive muscle weakness and wasting
what is segmental muscle necrosis
destruction of a portion of the myocyte length
what is muscle regeneration
satellite cells reconstitute destroyed muscle
what is fiber hypertrophy in response to
increased load (working out)
what is myotonia
tonic spasm of one or more muscles
a condition characterized by such spasms
what is hypotonia
deficient tone or tension
what is arthrogryposis
fixation joints in an extended or flexed potions
what is gowers sign and what does it indicate
use the hands and arms to “walk” up from a squatting position
indicates weakness of proximal muscles
what is the pneumonic for type 1 fiber types and what does it mean
"one slow fat red ox" type 1 fibers slow fibers lipid rich (fat) high myoglobin (red) oxidative (ox)
what is grouped atrophy
loss of motor neuron leads to atrophy of associated muscle
what is denervation atrophy
disorder of motor neurons
breakdown of myosin and actin
resorption of myofibrils
Spinal muscle atrophy (SMA) is what and cased by what
progressive distortion of anterior horn cells and cranial nerve motor neurons
AR- Survival Motor Neuron 1 (SMN1)
what is seen histologically in spinal muscle atrophy (SMA)
panfascicular atrophy with scattered large fibers 2-4x normal size
Duchenne Muscular Dystrophy (DMD) is caused by what
dystrophin defect from abnormal gene at Xp21 (deletion most of the time)
X-linked
DMD manifests when and what is the timeline from there
manifests before 5
wheel chair by 12
death in 20s
what does DMD present as
normal at birth
delayed walking then clumsy
weak pelvic then shoulder girdle
pseudo hypertrophy of calves as fivers increase in size
increased CK (returns to normal with muscle loss)
what causes death in DMD
respiratory failure
cardiac decompensation
lung infection
Becker Muscular Dystrophy is due to what
defect in dystrophin quality/quantity of protein from abnormal Xp21
the onset of becker’s is what compared to DMD
backers has later onset, is less severe and less common
