Resection of giant ethmoid osteoma with orbital and skull base extension followed by duraplasty

Osteomas of ethmoid sinus are rare, especially when they involve anterior skull base and orbit, and lead to ophthalmologic and neurological symptoms.

The present case describes a giant ethmoid osteoma. Patient symptoms and signs were exophthalmos and proptosis of the left eye, with progressive visual acuity impairment and visual fields defects. CT/MRI scanning demonstrated a huge osseous lesion of the left ethmoid sinus (6.5 cm × 5 cm × 2.2 cm), extending laterally in to the orbit and cranially up to the anterior skull base. Bilateral extensive polyposis was also found. Endoscopic and external techniques were combined to remove the lesion. Bilateral endoscopic polypectomy, anterior and posterior ethmoidectomy and middle meatus antrostomy were performed. Finally, the remaining part of the tumor was reached and dissected from the surrounding tissue via a minimally invasive Lynch incision around the left middle canthus. During surgery, CSF rhinorrhea was observed and leakage was grafted with fascia lata and coated with bio-glu. Postoperatively, symptoms disappeared. Eighteen months after surgery, the patient is still free of symptoms.

Before management of ethmoid osteomas with intraorbital and skull base extension, a thorough neurological, ophthalmological and imaging evaluation is required, in order to define the bounders of the tumor, carefully survey the severity of symptoms and signs, and precisely plan the optimal treatment. The endoscopic procedure can constitute an important part of surgery undertaken for giant ethmoidal osteomas. In addition, surgeons always have to take into account a possible CSF leak and they have to be prepared to resolve it.