Solitary extra-skeletal sinonasal metastasis from a primary skeletal Ewing's sarcoma.

INTRODUCTION: Ewing's sarcoma is a rare, malignant tumour predominantly affecting young adolescent males. We describe a unique case of an isolated extra-skeletal metastasis from a skeletal Ewing's sarcoma primary, arising in the right sinonasal cavity of a young man who presented with severe epistaxis and periorbital cellulitis.

RESULTS: Histologically, the lesion comprised closely packed, slightly diffuse, atypical cells with round, hyperchromatic nuclei, scant cytoplasm and occasional mitotic figures, arranged in a sheet-like pattern. Immunohistochemical analysis showed positive staining only for cluster of differentiation 99 glycoprotein. Fluorescent in situ hybridisation identified the Ewing's sarcoma gene, confirming the diagnosis.

MANAGEMENT: Complete surgical resection was achieved via a minimally invasive endoscopic transnasal approach; post-operative radiotherapy. Ten months post-operatively, there were no endoscopic or radiological signs of disease.

CONCLUSION: Metastatic Ewing's sarcoma within the head and neck is incredibly rare and can pose significant diagnostic and therapeutic challenges. An awareness of different clinical presentations and distinct histopathological features is important to enable early diagnosis. This case illustrates one potential management strategy, and reinforces the evolving role of endoscopic transnasal approaches in managing sinonasal cavity and anterior skull base tumours.