OBJECTIVETo study the histologic features and immunohistochemical findings of interfollicular stromal cells in hyaline-vascular Castleman's disease (HVCD), and to explore the role of these stromal cells in the pathogenesis of this disease.

METHODSThe clinical findings and microscopic features of 23 cases of HVCD cases were reviewed. Immunohistochemical study for CCL21, MSA, CD21, CD35, S-100 and CD34 was carried out.

RESULTSAccording to the criteria proposed by Danon et al., stroma-rich variant of HVCD contained prominent interfollicular zone which occupied at least 50% of the lymph node area. In the current study, there were 14 cases of stroma-rich HVCD and 9 cases of conventional HVCD. Eleven of the stroma-rich HVCD had paraneoplastic pemphigus and contrastly, no pemphigus lesion obtained in all the 9 cases of conventional HVCD. The association between stromal cell hyperplasia and paraneoplastic pemphigus was statistically significant (P < 0.01).In all the conventional HVCD cases studied, CCL21 and MSA were positive in the stromal cells.The stromal cells in 13 of the 14 cases of the stroma-rich HVCD were also positive for CCL21 and MSA, however, staining for CD21, CD35, S-100 and CD34 was negative in both groups. There was no statistical significance obtained (P > 0.05) between the differences of the staining results.

CONCLUSIONSStroma-rich HVCD and conventional HVCD represent two distinctive histologic variants and have a different association with paraneoplastic pemphigus. Most of the stromal cells locating in the interfollicular areas are fibroblastic reticular cells in origin, with the immunophenotype as CCL21(+)/MSA(+)/CD34⁻/CD21⁻/S-100⁻. The stromal cells proliferation correlate with the occurrence of paraneoplastic pemphigus, nevertheless, more cases are expected for a further study of the underlying pathogenesis.