A CASE OF EXTRASKELETAL EWING'S SARCOMA/PNET PRESENTING AS A MEDIASTINAL MASS

The Ewing's sarcoma/PNET family of tumors comes under small round blue cell tumors (SRBCT's). These are high grade relatively rare malignant neoplasms affecting children and young adults predominantly in 2nd decade. Most of these are seen affecting major long bones like femur, pelvis and ribs. Cases of extraskeletal Ewing's saroma (EES) involving chest wall, pleura, mediastinum, retroperitoneum, paravertebral region, lower extremities and even very few cases of isolated maxillary sinus Ewing's sarcoma have been reported.([1]) These malignancies are characterized by a chromosome 22 rearrangement.([2]) They are highly aggressive tumors with a high incidence of local recurrence and distant metastases.([3]) Recent studies suggest that this tumour is likely to originate from primitive stem cells and degree of malignancy depends upon the stage of stem cell arrest during differentiation. PNET shows variable degree of neuroectodermal differentiation.([4])