Abstract
Mesenchymal chondrosarcoma (MCS) is an unusual tumor mainly found in the skeleton. Around third of the cases occur in extra-skeletal sites with the orbit being the third most common site in these cases. In previous reviews of the orbital cases, it has been concluded that orbital MCS tends to occur in women in the second or third decades of life. However, 8 cases of orbital MCS have been reported so far in the pediatric age group (age less than 18 years-old) one of which has been considered congenital MCS in a 5-days old newborn girl. We describe 3 additional pediatric cases with primary orbital MCS and they were all males. Our cases presented with proptosis and calcific orbital masses on imaging studies. Histopathological examination of the excised masses shared the typical presence of undifferentiated mesenchymal cells and immature areas of cartilage. The diagnosis of MCS was further confirmed by immunohistochemical staining. Brief review of the literature in relation to this diagnosis in the orbit is also presented.