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Localized lymphoid hyperplasia of the rectum representing progressive
transformation of the germinal center. A report of two cases.APMIS.
2007 Dec;115 (12):1432-6.
Histologically,
benign lymphoid hyperplasia (BLH) of the rectum is usually
characterized by large lymphoid follicles with active germinal
centers, and a narrow surrounding mantle zone and marginal zone. We
present two cases of BLH of the rectum demonstrating progressive
transformation of the germinal center (PTGC). The patients were 50-
and 71-year-old Japanese women. Colonoscopy demonstrated small sessile
polyps in both cases. The resected specimen contained numerous
lymphoid follicles with active germinal centers and a portion of the
lymphoid follicles exhibited PTGC. The area showing PTGC contained a
few large lymphoid cells resembling lymphocytic and histiocytic
Reed-Sternberg cells of nodular lymphocyte-predominant Hodgkin
lymphoma. These PTGC contained small- to-medium clusters of
epithelioid cells in both cases. In situ hybridization studies
demonstrated scattered Epstein-Barr virus (EBV)-encoded small
RNA-positive medium and large lymphoid cells and crypt epithelium in
both lesions. EBV may be involved in the etiology of a subset of BLH
of the rectum. However, reactivity of lymphoid cells for EBV has been
reported in lymphoid tissues in a high percentage of "normal"
individuals. The etiology of BLH of the rectum remains unclear. |
