Two cases of histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto's disease) following diffuse large B-cell lymphoma.

Histiocytic necrotizing lymphadenitis (HNL) is often mistaken for malignant lymphoma clinically and is also sometimes difficult to differentiate from lymphoma even histopathologically. In this report, we describe the first 2 reported cases of HNL following non-Hodgkin's lymphomas. The patients were 27- and 30-year-old women who developed cervical and axillary lymph node swellings, respectively, in the course of remission of diffuse large B-cell lymphoma. The affected lymph nodes showed the typical histology of HNL: irregular-shaped "necrotic" foci with histiocytes engulfing apoptotic bodies intermingled with large-sized blastic lymphocytes. These findings mimicked the partial involvement of large-cell lymphoma. However, the blastic cells were almost exclusively T cells, and numerous apoptotic bodies were present, which excluded the possibility of recurrence of diffuse large B-cell lymphoma.