Transcript Diapositive 1

CH18
IMAGING APEAREANCE OF
ASKIN TUMORS: ABOUT 5
CASES
MA. JELLALI, M. AMOR, A. ZRIG, W. MNARI, M.
MAATOUK, W. HARZALLAH, R. SALEM, M. GOLLI.
Radiology service, FB Hospital, Monastir, Tunisia.
OBJECTIVES
 Askin’s tumor is a rare malignant tumor arising from the
chest wall. It affects mainly children and young adults.
 The aim of this work was to demonstrate the value of
imaging in the diagnosis and management of this tumor.
MATERIALS AND METHODS
 We retrospectively collected five cases of Askin’s tumor
of childhood.
 All our children underwent chest radiography and chest
CT scans, and two patients were also evaluated by
thoracic MRI.
 Radioguided biopsy for the diagnosis was performed in
all cases.
RESULTS
 The radiographic appearance of these tumors was not
specific.
 The CT scans can specify the size of the mass,
demonstrate their possible intrathoracic invasion and rib
erosion.
 The MRI can be helpful in the evaluation of the
mediastinum and the degree of pleural-based disease
along with any extrathoracic extension especially the
brachial plexus.
A 15-year-old boy patient presented with chest pain.
chest radiography showed a opacity posterior parietal
of the right basis thoracic
Chest CT scan confirms the presence of a parietal mass
with costal lysis and contralateral pulmonary metastases
A 11-year-old boy patient presented with chest pain.
Chest radiography showed a large left apical opacity with lytic lesion in second rib
Chest CT scan showed a mass occupant almost all the left pulmonary
hemifield. The lytic lesion of the rib moving towards the parietal origin
Chest radiograph of a 9 year old girl: right
posterior opacity with acute pleural connection
CT chest scan showed costal lysis associated with pleural
effusion moving towards the parietal origin
Chest CT scan: right apical mass with costal and vertebral lysis
MRI showed an intracanalar and parietal extension
DISCUSSION
 Askin tumor is a primitive neuroectodermal tumor
located in the thoracopulmonary region.
 Most of the tumors arise from the soft tissue of the
chest wall. Some tumors have also been found in
the lung.
 The disease is diagnosed by histologic and
immunohistochemical analysis.
DISCUSSION
 Cytologic smears of the tumor reveal small round
malignant cells that contain little cytoplasm and
are arranged in rows. The typical feature is the
presence of Homer-Wright rosettes with various
layers of cells with fibrillary material.
 Under immunohistochemical examination, the
tumor is positive for several neural markers, such
as NSE, CD99, and vimentin.
DISCUSSION
 The chromosomal translocation t(11;22)(q24;q12)
is an additional firm diagnostic criterion.
 Conventional radiography usually shows a mass
of various size accompanied by calcifications,
erosions of the ribs, pleural effusions, and even
pneumothorax.
 Typical CT findings include a large soft tissue
mass based on the signal chest wall with or
without ipsilateral pleural effusion and rib
destruction.
DISCUSSION
 Large lesions often have a heterogeneous
appearance, representing hemorrhage and
necrosis or cystic degeneration. Calcification
within the mass and lymphadenopathy are rare.
 The mass tends to displace, rather than encase
the adjacent organ. Linear and nodular density in
the subpleural fat, which may represent local
perilymphatic and perineural extension, is an
unfavorable prognostic sign.
DISCUSSION
 After intravenous contrast administration, the
tumors demonstrate a heterogeneous appearance
with non- enhancing necrotic or cystic areas.
 According to the literature, characteristic MRI
findings include hyperintensity compared with
muscle on T1-weighted imaging and
heterogeneously bright signal intensity on T2weighted imaging representing hemorrhage and
necrosis.
DISCUSSION
 Post-contrast T1-weighted imaging can
demonstrate the boundary and parenchyma of the
tumor, as well as the blood supply of the mass.
 Nevertheless, the radiologic characteristics of
Askin tumors are not specific, but imaging can be
valuable for evaluating the extent of the tumor, the
response to treatment and local recurrences or
distant metastases.
DISCUSSION
 It is also useful for guiding the biopsy route and
determining whether the tumor has been
completely resected.
 MRI is more sensitive in evaluating local invasion
by providing true multiplanar imaging and excellent
soft tissue differentiation, but CT is better for
detecting lung and remote metastases, especially
bony detail.
CONCLUSION
 Askin’s tumor of neuroectodermal origin is a particular
form of bone tumors of the chest wall.
 It should be considered in the differential diagnosis of
any thoracopulmonary mass in childhood and
adolescence through appropriate histology and
immunohistochemistry of incisional biopsies.
 The association with rib lysis comfort the diagnostic.