[Ewing sarcoma osseous and extraosseous : a clinicopathologic study of 29 cases].
BACKGROUND
Ewing's sarcoma (ES) is a rare tumour accounting for 10% of primary malignant bone tumours in children and 3% of all childhood malignancies. ES belongs to a group of small round cell tumours.


OBJECTIVE
In this review, we will describe the main clinicopathological features of this rare tumour and discuss its prognosis.


METHODS
We report a retrospective study of 29 cases of ES, of which 4 were extraosseous, diagnosed over a period 11 years (January 1989 - December 1999). Clinicopathological data were described. Hematoxylin-eosin staining and immunohistochemical study were reviewed.


RESULTS
12 patients were male and 17 were female (ratio: 0,8) with a median age of 16 years. 62,5% of tumours were located in flat bone and 33,3% in long bone. The medium size of the tumor was 10,6 cm (range:3-25cm). 27,5% of patients presented with metastatic disease at time of diagnosis. Microscopically, tumour tissue was composed of round, small, blue cells with fine granular chromatin. Tumour cells strongly coexpressed CD99 and vimentin (100%). Systemic treatment consisted of adjuvant chemotherapy (84,2%). Local control was based on and surgery (57,9%) or radiation therapy (36,8%). A good response to chemotherapy was obtained in 37.5%; 13,7% of patients were alive without disease (medium follow up: 169 mois); 34,5% of patients developed metastases (medium follow up : 23 months) and 10,3% developed recurrences (medium follow up :13 months).


CONCLUSIONS
Our study emphasizes two points : the great size of the tumor and the frequent location in flat bone which may explain the poor prognosis of Ewing sarcoma in our series despite the multidisciplinary treatment.
Laboratoire d'anatomie et cytologie pathologiques.
Lobna
L
Ayadi
Chiraz
C
Chaari
Rim
R
Kallel
Kamel
K
Ayadi
Abdelmajid
A
Khabir
Rachid
R
Jlidi
Jamel
J
Daoud
Mounir
M
Frikha
Saloua
S
Makni
Tahya
T
Sellami-Boudawara
D000293:Adolescent; D000328:Adult; D001859:Bone Neoplasms / Q000473:pathology*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008175:Lung Neoplasms / Q000556:secondary; D008297:Male; D012189:Retrospective Studies; D012512:Sarcoma, Ewing / Q000473:pathology*; D055815:Young Adult