Objective: To test the recent hypothesis that lymphomatoid granulomatosis (LYG) is a clonal B-cell proliferative process related to Epstein-Barr virus (EBV).
Background and design: Historically, LYG has been classified as an angiocentric T-cell lymphoproliferative disorder. To further characterize LYG in the skin, we analyzed for EBV RNA in lymphocytes using in situ hybridization, coupled with colabeling for B-cell and T-cell markers. Clonality of lymphocytes was assessed by polymerase chain reaction using primers for immunoglobulin heavy chain genes and T-cell receptor beta and gamma genes.
Setting: Academic referral center.
Patients: In a 5-year retrospective review, we identified 4 patients with classic clinical and pathologic features of LYG in skin and lung, and tissue available from both sites.
Main outcome measures: The presence or absence of EBV RNA and clonal gene rearrangements in cutaneous and pulmonary lesions of LYG.
Results: Biopsy specimens of skin and lung in all patients revealed angiocentric infiltrates predominantly composed of T lymphocytes. Epstein-Barr virus RNA was identified in the skin of 1 patient and the lung of 3 patients, and was restricted to B cells. Polymerase chain reaction revealed clonal immunoglobulin heavy chain gene rearrangements and no clonal rearrangement of T-cell receptor genes in skin and lung tissue of all patients.
Conclusions: At least some examples of LYG in the skin and lung are characterized by a clonal proliferation of B lymphocytes, some of which contain EBV RNA. The B cells are typically scarce and may be obscured by striking angiocentric T-cell infiltrates.