Ewing's family of tumors of the sinonasal tract and maxillary bone.

The Ewing's family of tumors (EFT) are malignant neoplasms affecting children and young adults. Most cases arise in the long bones or the pelvis. Primary EFT of head and neck is uncommon and primary sinonasal EFT is even rarer. Previous studies have not focused on the sinonasal region specifically, and the published literature on sinonasal EFT consists of sporadic case reports. Fourteen cases of sinonasal EFT were available and had H&Es for review and immunohistochemical stains for CD99, S100, keratins, synaptophysin and desmin. FISH or RT-PCR was performed for EWSR1 abnormalities on 8 cases. The 14 identified patients included 5 males and 9 females, ranging from 7-70 years of age (mean 32.4 years). Tumors involved nasal cavity (5), sinuses (5) or both (4). Five patients had dural, orbital or brain involvement. The majority involved bone radiologically and/or microscopically. All cases were composed of small cells with variable cytoplasmic clearing. Focal or prominent nesting was noted in most cases. All cases were positive for CD99. Keratins (AE1/3 and/or CAM5.2), S100 and synaptophysin were positive in 4, 3 and 5 cases, respectively. All cases were negative for desmin. The 8 cases tested by FISH or RT-PCR were positive for EWSR1 abnormalities. Follow-up in 8 patients ranged from 1-168 months (average 11.3 m) showing 1 death due to metastatic disease, 1 death due to local disease, 1 patient alive with metastases and 5 patients disease-free at last follow-up. Interestingly, however, an analysis of the literature suggests a better prognosis for sinonasal EFT than EFT overall.