OBJECTIVETo study the prevalence of IgG4-positive plasma cells in Rosai-Dorfman disease and to assess the association between Rosai-Dorfman disease and IgG4-related sclerosing disease (IgG4-SD).

METHODSThe clinicopathologic features of 12 tissue samples of Rosai-Dorfman disease (11 extranodal and one nodal) from nine patients were reviewed. The degree of fibrosis and occlusive phlebitis was studied by HE staining. The expression of IgG4 and IgG in plasma cells were studied by immunohistochemistry (EnVision) and quantitatively analyzed by medical image analysis system.

RESULTSNine tissue samples showed different degree of fibrosis (four tissue samples were mild, one tissue sample was moderate and four tissue samples were severe) and two tissue samples showed occlusive phlebitis in the lesional tissue. Immunohistochemical study showed marked infiltration by IgG4-positive plasma cells (> 50 per high-power field) in four tissue samples, moderate infiltration (30 to 50 per high-power field) in two tissue samples, mild (10 to 29 per high-power field) in three cases and negative infiltration (< 10 per high-power field) in three tissue samples (P < 0.01). Three tissue samples fulfilled the diagnostic criteria of IgG4-SD (> 50 IgG4-positive plasma cells per high-power field and IgG4-to-IgG ratio > 40%), including one tissue sample each of Rosai-Dorfman disease in the left facial skin, above the left eye socket, and in the right parotid.

CONCLUSIONSSome cases of Rosai-Dorfman disease fulfill the diagnostic criteria and show the histologic features of IgG4-SD. They may represent members of the IgG4-SD spectrum. The detection of IgG4-positive plasma cells in the lesional tissues of Rosai-Dorfman disease may have clinical pathological significance.

Fibrosis ; Histiocytosis, Sinus ; diagnosis ; immunology ; Humans ; Immunoglobulin G ; chemistry ; Immunohistochemistry ; Phlebitis ; pathology ; Plasma Cells ; chemistry

Primary Sjogren's syndrome (pSS) is a chronic autoimmune disease with welldocumented association of lymphoid malignancies during the progress of the disease. Although several types of malignancy and pseudomalignancy have been reported in pSS, low-grade non-Hodgkin's lymphomas are the most frequently observed. Reactive plasmacytosis mimicking myeloma is a very rare condition in association with pSS. We describe a 72-yr-old woman with pSS who presented with hypergammaglobulinemia, and extensive bone marrow and lymph node plasmacytosis, which mimicked multiple myeloma. In this patient, there was an abnormal differentiation of memory B cells to plasma cells in the peripheral blood suggesting underlying pathogenetic mechanism for this condition.
Aged ; Antigens, CD19/analysis ; Antigens, CD27/analysis ; Bone Marrow Examination ; Diagnosis, Differential ; Female ; Fluorescent Antibody Technique/methods ; Humans ; Multiple Myeloma/*pathology ; Plasma Cells/chemistry/*pathology ; Sjogren's Syndrome/*pathology