Evolution of a primary lymphoma of the orbit.

A patient with a histologically benign lymphoid pseudotumour of the orbit developed a recurrent mass which proved to be a well differentiated lymphocytic lymphoma. Immunohistological studies showed that a majority of cells in the pseudotumour bore the same immunological markers as the subsequent lymphoma. There were no clinical or radiographic features of the initial lesion which indicated its eventual malignant course.