Orbital lymphomas and pseudolymphomas: treatment with radiation therapy.

A retrospective analysis of 16 patients with orbital lymphoma or pseudolymphoma from 1961-1984 was undertaken to evaluate the use of radiation therapy. Pathologic assessment confirmed that four patients had benign pseudolymphoma, and 12 patients had true malignant lymphoma, including two with advanced disease at presentation. With a median follow-up of 4 years, the local control rate with radiation therapy was 100%, although the two patients with advanced disease died of lymphoma 26-33 months after irradiation. While doses of 1,600-2,000 cGy appear adequate for pseudolymphoma, for lymphoma a dose of 3,000-4,000 cGy is necessary. Subconjunctival lesions can be treated in a single anteroposterior field; retroorbital lesions require an additional lateral field.