Muscle Tissue Pathology Flashcards
what is myasthenia gravis?
autoimmune or congenital neuromuscular disease
muscle weakness
antibodies block ach receptors at the postsynaptic neuromuscular junction
inhibits excitatory effects at nicotinic receptors
what are diplopia and ptosis and what are they a symptom of?
ptosis is drooping of eyelid
diplopia is double vision
–myasthenia gravis
rhabdomyosarcoma
malignant tumor of skeletal muscle
t(2;13) translocation
alveolar rhabdomyosarcoma
endomysial cd8 tcells (cell mediated)
polymyositis
polymyositis
sarcoma of retroperitoneum and deep soft tissues
malignant fibrous histiocytoma
vimentin immunohistochemical stain signifies what?
sarcoma/rhabdomyosarcoma
liposarcoma
most common soft tssue sarcoma in adults, large,
+ for myogenin
pleomorphic rhabdomyosarcoma
most common malignant tumor in adults
liposarcoma
endomysial inflammation (CD*+ t cells) with necrotic muscle fibers; skin is not involved
polymyositis
antibodies against presynaptic Ca channels of the NeuroMuscularJunction
lambert-eaton syndrome
which resonds poorly to glucocorticoids, dermatomyositis or polymyositis or inclusion body myositis?
inclusion body myositis
telangiecstasias
dilated capillary loops (dermatomyositis)
rhabdomyosarcoma is frequent in…
children, head and neck, gentourinary, retroperitoneum
what do you treat dermatomyositis with?
corticosteroids
myasthenia gravis ______ with exertion
worsens
what arises as a paraneoplastic syndrome due to small cell carcinoma of the lung
lambert-eaton syndrome
neuron specific enolase immunohistochemical stain
neoplasms with neuronal differentiation
nodular fasciitis follows…
trauma
cause of and clinical features of lambert-eaton syndrome?
cause: presynaptic ca channels cannot fire so acetylcholine is not released
findings: proximal muscle weakness that improves with use, eyes usually not affected, anticholinesterase agents do not help, and resolves with resection(removal) of cancer
most sarcomas are ____+ and most carcinomas are ____+
vimentin ; cytokeratin
fibrous septae dividing cells into clusters
t(2;13)
children
alveolar rhabdomyosarcoma
Lab findings of dermatomyositis?
increase creatine kinase +ANA, + anti-Jo1 antibody
what defect causes x linked muscular distrophy?
mutated dytrophin gene (xp21)
spontaneous - large gene size predisposes to high mutation rate
muscle weakness that worsens with use and improves with rest
myastheni gravis
UPS
undifferentiated pleomorphic sarcoma
lack of differentiation, deep in extremities, poor prognosis
sheets of anaplastic bizarre cells/nuclei, high mitotic rate
what is chronic inflammation of multiple muscles?
polymyositis
Causes of duchenne and becker muscular dystrophies
duchenne - deletion of xp21 (dystrophin)
becker - mutated dystrophin (xp21)
what type of tumor is associated w tuberous sclerosis??
cardiac rhabdomyoma
synovial sarcoma
found in joint or deep tissue
arise from mesenchymme not synovium
malignant tumor of adipose
liposarcoma
how do you treat myasthenia gravis?
acetylcholinesterase inhibitors or anticholinesterase agents
immunosuppressants
in selected cases, thymectomy(if thymic hyperplasia or thymoma present)
white superficial nodules (plantar palmar penile) or deep large and infiltrative in girdles and abdominal cavity
low mitotic activity
fibromatosis
most common benign adult soft tissue tumor
lipoma
dematomyositis
most common post-irradiation soft tissue sarcoma
malignant fibrous histiocytoma
marker for epithelial originating tumors
cytokeratin
what is a systemic CT disease that causes inflammation of the skin and muscle?
dermatomyositis
perimysial CD4/b cells
dermatomyositis
duchenne muscular dystrophy
in rhabdomyosarcoma, a t(2;13) translocation does what?
makes a PAX3-FKHR protein that disregulates muscle differentiation
diplopia and ptosis are signs of
myasthenia gravis
autoantibodies against presynaptic Ca++ channels and block Ach release
eaton lambert syndrome
histology comparison of dermatomyositis and polymyositis
DM: lymphocytes (mostly B cells) are perivascular and parimysial; atrophic muscle fibers are at periphery and not next to lymphocytes –> intramuscular capillaries are main immune attack site PM: lymphocytes (cd8 T cells) and macrophages surround strophic/necrotic muscle tissue –> muscle fibers are directly injured by cell-mediated immune attack
rimmed vacuoles like polymyositis with endomysial cd8 infiltrates
inclusion body myositis
clinical features of dermatomyositis?
bilateral proximal muscle weakness -distal involvement later on heliotrope rash on upper eyelids malar (facial butterfly) rash Gottron papules (scaly erythematous papules on elbows, knuckles, and knees)
boytryoides
grape like - assocaiated form of rhabdomyosarcoma
benign tumor of adipose
lipoma
how does duchenne muscular dystrophy present?
1 yo - proximal muscle weakness –> progresses to distal muscles
elevates serum CK and calf pseudohypertrophy
death usually from cardiac or respiratory failure (myocardium involvement)
most common malignant soft tissue tumor in children
rhabdomyosarcoma
strap cell mimicking skeletal muscle cross striations
rhabdomyosarcoma indicator
eaton lambert syndrome ________ with repetitive stimulation
improves
degenerative disorder characterized by muscle wasting and replacement of skeletal muscle by adipose tissue
x linked muscular dystrophy
herringbone pattern in histology
fibrosarcoma
benign tumor of skeletal muscle
rhabdomyoma
What is dystrophin?
cytoplasmic protein that anchors the muscle fiber cytoskeleton to the extracellular matrix
autoantibodies against AcH receptors
myasthenia gravis
rhabdomyosarcoma: characteristic cell? desmin + or -? most common site?
rhabdomyoblast
desmin +
head and neck (vagina for young girls)
amyotrophic lateral sclerosis (ALS)
upper and lower motor neuron damage causing muscle atrophy and weakness
muscle denervation
affects cerebral cortex
not selective - can affect type 1 and 2 muscle fibers
early atrophy is angular and scattered but later on grouped
