Angioimmunoblastic T-cell lymphoma with hyperplastic germinal centers: a clinicopathological and immunohistochemical study of 10 cases
Abstract:An absence of germinal centers is one of the histological characteristics of angioimmunoblastic T-cell lymphoma (AITL). We report here 10 unusual cases of AITL with hyperplastic germinal centers. The clinical presentation of each patient was characterized by generalized lymphadenopathy, constitutional symptoms and polyclonal hypergammaglobulinemia. The initial biopsy findings of each patient were similar and were characterized by hyperplastic germinal centers with ill-defined borders and a proliferation of high endothelial venules (HEV). In the paracortical area there was a mixed infiltrate including irregularly shaped clusters or small nests of clear cells in all cases. Moreover, the clear cells invaded the lymphoid follicles, resulting in expansion of the germinal centers, except for one case. Immunohistochemistry revealed that the tumor cells, including clear cells, were CD4-expressing T cells. Some of the atypical lymphocytes were also Bcl-6-positive. A majority of the follicular dendritic cell networks showed a normal/reactive or an expanded/disrupted pattern in all cases. Moreover, three lesions possessed a few large irregularly shaped proliferations of follicular dendritic cells around the HEV. Four cases progressed to AITL within a few years. The present 10 cases probably represent an early stage of AITL preceding follicular dendritic cell hyperplasia. Detection of clear cells, Bcl-6-positive atypical T lymphocytes, and foci of irregularly shaped proliferation of follicular dendritic cells appears to be critical for early diagnosis and treatment of AITL with hyperplastic follicles.
Document Type: Original Article
Affiliations: 1: Department of Anatomic and Diagnostic Pathology, Dokkyo University School of Medicine, Mibu, Japan, 2: Department of Pathology and Genetics, Aichi Cancer Center Hospital, Nagoya, Japan, 3: Department of Pathology and Clinical Laboratories, Maebashi Red Cross Hospital, Maebashi, Japan, 4: Department of Pathology, Kitasato Medical Center Hospital, Kitamoto, Japan, 5: Department of Pathology and Clinical Laboratories, Gunma Cancer Center Hospital, Ohta, Japan, 6: Pathology Department, Gunma Health Foundation, Maebashi, Japan
Publication date: October 1, 2001