Epstein-Barr virus-related reactive lymphoproliferative disorders in middle-aged or elderly patients presenting with atypical features. A clinicopathological study of six cases.

We report six cases of Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) in middle-aged and elderly patients exhibiting atypical clinical findings. The patients, two males and four females, ranged in age from 52 to 74 years, with a median age of 64 years. Clinically, they were characterized by tonsillar tumor, cervical lymphadenopathy, and absence of atypical lymphocytosis of the peripheral blood. "B"symptoms were recorded in only two cases. Pancytopenia was recorded in one case during the disease course. The clinical course was self-limited. Histologically, all lesions were characterized by effacement of the follicles and expansion of the interfollicular area with proliferation of small vessels, indicating atypical lymphoid proliferation. In the interfollicular area, there was a mixed infiltrate, including small-to-medium-sized lymphocytes, plasma cells, and T-and B-immunoblasts. Immunoblasts resembling Reed-Sternberg cells were observed in four lesions. Three lesions contained numerous mature plasma cells, plasmacytoid cells, and immature plasma cells in some areas. In situ hybridization demonstrated a varying number of EBV-infected lymphocytes in the interfollicular area. The overall histomorphologic findings of the present six cases were similar to those of infectious mononucleosis (IM) in younger patients. However, the clinical findings were quite different from those of IM in the younger age population. To avoid overdiagnosis and overtreatment, we emphasize the need to be aware of the atypical clinical presentation of EBV-related LPDs in middle-aged or elderly patients, and to turn careful attention to these clinical and laboratory findings as well as to the morphologic features.