Purpose: To determine whether the use of polymerase chain reaction for B-cell gene rearrangement in patients with orbital lymphoid infiltrate disorders could be useful in the diagnosis of lymphoma, especially, in differentiating benign lesion from malignant one.
Methods: In addition to clinical, pathological, and immunohistochemical evaluations, 48 cases of orbital lymphoid infiltrate disorders were examined for immunoglobulin heavy (IgH) gene rearrangement by means of PCR to amplify the FR3 region with formalin-fixed and paraffin-embedded tissues.
Results: Gene rearrangement in the third frame-work of the IgH region was detected in specimens obtained from 15 cases of malignant lymphoma, 4 of reactive lymphoid hyperplasia and 3 of orbital pseudotumor. All of these patients showed a discrete band (100 bp) which reflected monoclonal proliferation of B lymphocytes. 5 cases of malignant lymphoma, 6 of reactive lymphoid hyperplasia and 15 of orbital pseudotumor did not show a discrete band on PCR.
Conclusions: The FR3 region gene rearrangement of Ig heavy in patients with orbital lymphoid infiltrate disorders may be an additional diagnostic tool in differentiating benign from malignant lymphoid diseases and in offering a useful adjunct for diagnosis in difficult or unclear cases. It is a reliable and practical method of gene diagnosis in orbital lymphoid infiltrate disorders and helps to identify the molecular mechanism of malignant lymphoma.