[Clinicopathologic characteristics and immunophenotypes of histiocytic necrotizing lymphadenitis: an analysis of 84 cases].

OBJECTIVE

To study the clinical manifestation, pathologic features and immunophenotype of histiocytic necrotizing lymphadenitis (HNL).

METHODS

The clinicopathologic data of 84 patients with HNL from 2005 to 2014 were retrospectively studied. Immunohistochemical staining using EliVision method for CD20, PAX5, CD3, CD45RO, CD4, CD8, CD56, CD68, CD123, granzyme-B, TIA1 and MPO was carried out. In-situ hybridization for Epstein-Barr virus RNA was performed on archival lymph node biopsy tissue.

RESULTS

Immunohistochemical study showed that the lesional cells were predominantly histiocytes (CD68+), plasmacytoid dendritic cells (CD123+) and T lymphocytes (CD3+ and CD45RO+). Clusters of CD68-positive cells with strong and diffuse MPO expression were identified. T lymphocytes with CD4 and CD8 positivity were noted. CD56+ natural killer cells and CD20+/PAX5 B cells were rare. Apoptosis-related markers, including TIA1 and granzyme B were expressed by T lymphocytes and histiocytes in lymph nodes of HNL. In-situ hybridization for Epstein-Barr virus RNA was positive in only 10.0% of the cases.

CONCLUSIONS

HNL shows no specific clinical and laboratory findings. Recognition of the characteristic histopathologic changes in lymph node biopsy of HNL is the key to correct diagnosis. Immunohistochemical study using a panel of markers, including CD3, CD4, CD8, MPO, CD123, granzyme-B and TIA1, is helpful in the differential diagnosis of HNL.