Lymphomatoid Granulomatosis

Lymphomatoid granulomatosis (LG) is a rare, Epstein-Barr virus (EBV)-positive, B-cell lymphoproliferative disorder often accompanied by an exuberant reactive but cytotoxic T-cell infiltrate. The density of the T-cell infiltrate led to the initial impression that LG was a T-cell malignancy. Also, LG used to be included under the rubric of angiocentric lymphomas and shares many features with nasal-type, extranodal, natural killer (NK)/T-cell lymphoma (NKL). Both LG and NKL can present in the airways/nasal cavity, both are associated with an angiocentric, angiodestructive, and cytotoxic lymphoid infiltrate, and both are associated with EBV infection. However, the neoplastic, EBV-infected lymphoid cells of LG are of B-cell lineage and NK cell lineage in NKL. A broad clinical and pathologic spectrum is observed for LG, ranging from indolent and regressive disease to an aggressive large B-cell lymphoma. Consequently, controversy still surrounds the precise nosologic designation of LG as a reactive, inflammatory versus a neoplastic lymphoid process. Some cases of LG would be well characterized as immunosupression-related or posttransplant lymphoproliferative disorders and reduction of immunosuppression in many of these cases has been associated with resolution of disease. Other cases require aggressive chemotherapeutic agents to halt disease progression.