Burkitt lymphoma is a high-grade B-cell non-Hodgkin lymphoma. The endemic form of this malignancy occurs primarily in children aged 5 to 7 years, and it presents with jaw and facial bone involvement. The sporadic form affects older children (mean age: 12.2 yr) and often manifests as an abdominal mass; it rarely involves the head and neck. The presence of any type of lymphoma in the paranasal sinuses is rare. We report a case of Burkitt lymphoma that originated in the sphenoid sinus in a 66-year-old white woman. The patient presented with hypoesthesia in the left V1 and V2 distributions and frequent left-sided headaches. Imaging revealed that the destructive lesion had spread into the cavernous sinus and infratemporal fossa. Repeat imaging showed progression of the lesion in just 1 month. An endoscopic sphenoidotomy was performed to obtain a tissue specimen, and a diagnosis of sporadic Burkitt lymphoma was established on the basis of its clinical, morphologic, and immunohistochemical characteristics. The patient underwent chemotherapy and radiation. Short-term follow-up imaging showed that the lesion had disappeared, and the patient remained disease-free at 3 years of follow-up. This case is one of the few reported cases of true adult Burkitt lymphoma originating in the sphenoid sinus. We discuss the rapid progression of the disease and the considerable amount of invasion that can occur with minimal symptoms.