Primary esophageal lymphoma is very rare, with fewer than 25 cases documented in the English-language literature. We report a case of primary diffuse large B-cell lymphoma of the esophagus in a 42-year-old woman. Barium esophagogram revealed almost complete esophageal obstruction at the level of the cervical esophagus, and flexible endoscopy showed a circumferential submucosal tumor covered with intact mucosa. Neck magnetic resonance imaging (MRI) showed a wide cervical mass circumferentially encompassing the lumen of the cervical esophagus. Biopsies taken with multiple forceps during flexible and rigid esophagoscopy were nondiagnostic. Finally, external esophageal wall biopsies taken during neck exploration provided information that helped us establish the diagnosis. Pathohistological findings confirmed non-Hodgkin's lymphoma of the diffuse large B-cell type. The patient was treated with combined immunochemotherapy, consisting of rituximab plus cyclophosphamide, vincristine, adriablastin, and prednisone (CHOP), followed by irradiation. A complete response was achieved, and 3 years after diagnosis and treatment the patient was disease-free.