Reactive lymphoid hyperplasia of the lymph nodes with giant follicles: a clinicopathologic study of 14 Japanese cases, with special reference to Epstein-Barr virus infection.

To clarify the clinicopathologic and immunohistochemical features of reactive lymphoid hyperplasia with giant follicles (RHGF) among Japanese, 14 patients were studied. The subjects consisted of 9 males and 5 females, ranging in age from 9 to 61 years, with a mean age of 30 years and a median age of 24 years. None of the patients exhibited systemic symptoms. The affected lymph nodes were located in the head and neck area except in 1 case. At the time of lymph node biopsy, 1 patient was diagnosed as having acute infectious mononucleosis (IM) and 2 patients had a recent history of acute IM. One each with myelogenous leukemia or diffuse large B-cell lymphoma had a history of peripheral blood stem cell transplantation. There were no recurrences during follow-up periods ranging from 3 to 50 months. Histologically, 14 lesions were characterized by numerous enlarged, coalescing lymphoid follicles with distortion rather than effacement of the lymph node architecture. By in situ hybridization, Epstein-Barr virus (EBV) genomes were demonstrated in 5 (36%) of 14 cases. The present study indicates that a portion of RHGF appears to represent a histologic finding of acute IM. Moreover, as previously stated, RHGF should be differentiated from follicular lymphoma, particularly the floral variant.