Isolated primary lymphomatoid granulomatosis of central nervous system.

Lymphomatoid granulomatosis (LG) is an infrequent extranodal Epstein-Barr virus (EBV)-associated B-cell lymphoproliferative disorder characterized by angiocentric and angiodestructive polymorphic lymphoid infiltration. CNS is involved in one of every 4 patients, but isolated CNS involvement at presentation is rare. A 67-year-old man was admitted to our hospital because of visual impairment. Magnetic resonance imaging (MRI) revealed a suprasellar mass lesion isointense to gray matter on T1 and T2-weighted images. The hypotalamic/chiazmatic mass was resected through a transsphenoidal approach. Pathological examination of the biopsy specimen revealed large atypical, CD20-positive B-lymphocytes within a background containing numerous CD3-positive small T-lymphocytes and scattered admixed plasma cells and histiocytes. Necrotic areas and vascular infiltration by a mixed mononuclear cell infiltrate with scattered large atypical lymphoid cells was present. In situ hybridization for EBV showed few large cells both around blood vessels and adjacent to the necrotic zone. This morphologic and immunophenotypic features was diagnostic for lymphomatoid granulomatosis. The patient was successfully treated with steroids, high-dose methotrexate and radiotherapy.