Fibromyxomatous spindle cell neoplasm of the ethmoid sinus with extension into the optic cavity: Report of a case and review of the literature

Introduction: Fibromyxomatous spindle cell neoplasms represent a recently described form of fibrous dysplasia. Case Report: A 43 year-old woman presented to our clinic with chronic sinusitis and an infiltrative ethmoid mass consistent with a large mycetoma. Clinical manifestations of the tumor included right frontal and para-orbital pain with proptosis and chronic eye-drainage. Comparison of CT images to prior studies demonstrated a slowly growing mass with diffuse enhancement in the right ethmoid complex with obstruction of the frontal sinus and erosion through the lamina papyracea. The tumor was removed, with subsequent pathology demonstrating a fibromyxomatous spindle cell neoplasm. Unfortunately, the tumor recurred following surgery, and within three months had grown to its initial size. Discussion: Myxomatous tumors are rarely found in the paranasal sinuses. Paranasal fibromyxomas have been reported in the literature. These rare tumors are characterized as aggressive lesions with a propensity for recurrence. In this manuscript, we present the first reported case of a fibromyxomatous spindle cell neoplasm occurring in the ethmoid sinuses. While immunohistochemistry is necessary to differentiate this lesion from paranasal myxomas, the clinical course of both entities appears similar. Conclusion: Fibromyxomatous spindle cell neoplasm is a rare tumor of the ethmoid sinus. This entity must be included in the differential diagnosis for an aggressively growing lesion of the para-nasal sinuses.