Rhabdomyosarcoma of the Paranasal Sinuses Initially Diagnosed as Acute Sinusitis

Rhabdomyosarcoma (RMS) is an uncommon soft tissue malignancy that is typically found in the pediatric population. Here we describe a rare case of widely metastatic alveolar RMS of the right paranasal sinuses in an adult woman who presented with several months of unilateral sinus symptoms that was initially misdiagnosed as acute sinusitis. A middle-aged female presented with two months of right sinus pressure and unilateral epistaxis. She had previously been diagnosed with acute sinusitis and was treated with antibiotics without improvement. Nasal endoscopy demonstrated a fungating right nasal cavity mass. On computed tomography scan (CT), she was found to have metastatic disease in the mediastinum, lungs, bones, pancreas, and right ovary. Pathology of the nasal cavity mass was consistent with alveolar RMS. The patient initially responded well to chemotherapy, but subsequently developed brain and leptomeningeal metastases. This case of sinonasal rhabdomyosarcoma is unique in the extent of metastatic disease at the time of diagnosis and the initial misdiagnosis despite concerning unilateral symptoms and imaging. This thus highlights the importance of maintaining a high index of suspicion for malignancy in patients with unilateral sinus symptoms.