Rhabdo Flashcards
what fusion mutations are found in ARMS
PAX-FOXO1 (usually PAX3 or PAX7)
most common fusion protein in ARMS
PAX3-FOXO1
T(2;13) in 60% of ARMS
2nd most common fusion protein in ARMS
PAX7-FOXO1
t(1;13) in 20% of ARMS
what is fusion negative RMS
do not have PAX3 or PAX7-FOXO1 (ERMS, spindle cell, botryoid RMS)
Genetic abnormalities in ERMS
Aneuploidy
RAS pathway activating mutations
p53 mutations
LOH 11p15.5 (enhanced IGF2 expression)
most common primary sites in RMS
head/neck
GU
extremity
syndromes associated with RMS
LFS Beckwith-Wiedemann Costello Noonan NF1 Gorlin Dicer1
Staging of RMS
MRI/CT of primary and regional nodes, CT chest, PET scan, bilateral bone marrow asp/biopsy, CSF if paramengingeal tumours, retroperitoneal LN assessment for paratesticular > 10 yrs or extremity RMS
favourable sites in RMS
orbit, non-parameningeal H+N, non-bladder/prostate GU, biliary tract
stage 1 RMS
localized tumour in favourable site
stage 2 RMS
unfavourable primary site, but small (=< 5cm) without node involvement
stage 3 RMS
unfavourable primary, localized but can be large
stage 4 RMS
all with distant mets
RMS grouping is based on what?
extent of resection before any therapy given
group III RMS
tumour biopsied but no surgical resection performed
prognostic factors for RMS
fusion status (fusion negative > fusion positive), histology, stage, group, age, metastatic disease, recurrent disease
morphology of ERMS vs ARMS
ERMS: spindle cell tumour
ARMS: small round blue cell tumour
RMS immunohistochemical stain
MyoD, Myogenin, Desmin, Muscle specific actin
growth pattern of botryoid tumours
grape-like, usually occurs in hollow organ like vagina or nasopharynx
spindle cell RMS - how common? outcome?
5-10% of cases
favourable prognosis
how common is fusion negative ARMS?
20% of ARMS
which sites require surgical assessment of LNs?
- paratesticular (> 10 yrs for RPLNA)
- extremity
where does RMS recur?
2/3 are local recurrences
Other: lung, bone, bone marrow
how do you decide RT field for RMS
determined by pre-treatment tumour size
treatment for intermediate risk RMS
VAC/VI x 45 weeks
treatment for low stage, low risk ERMS
VA +/- lower cyclophosphamide dose or shorter duration therapy
treatment for high risk RMS
standard therapy not defined
what is maintenance therapy and in what group can you consider it
vinorelbine/cyclophos x 6 months for IR patients
what do you do about residual masses after tx for RMS?
can be scar - may be followed without further tx
what type of RMS is associated with LFS?
typically embryonal histology with anaplasia
