[2128] Splenic Manifestation of Chronic Autoimmune Disease: A Report of Five Cases with Histiocytic Necrotizing (Kikuchi-Fujimoto-Like) Change in Four Cases with Use of 16s rDNA PCR To Exclude Infection

Nadine S Aguilera, Thomas A Summers, Binxue Zhang, Aaron Auerbach. Joint Pathology Center, Silver Spring, MD; Walter Reed National Medical Center, Bethesda, MD; Henry Jackson Foundation, Gaithersburg, MD

Background: Autoimmune diseases are often associated with enlarged lymph nodes and splenomegaly. The histologic findings in splenic white pulp and lymph nodes have been commonly described as follicular hyperplasia. Histiocytic necrotizing lymphadenopathy has also been described in autoimmune disease, but a similar counterpart in the spleen has not been documented.
Design: Five splenectomy specimens associated with autoimmune disease were retrieved from our files. An immunohistochemical panel for CD3, CD8, CD20, CD68, lysozyme, CD123, CD163, IgG4, Hemoglobin peroxidase, myeloperoxidase, kappa and lambda was performed in 4/5. Stains for infectious organisms and in situ hybridization for EBV (EBER) were also performed. A 16S rDNA PCR was performed on FFPE DNA samples isolated from 4/5 cases. The universal primer set [27f/1492r] targeting 16S rRNA gene for most eubacteria was applied to the assay. Clinical data was obtained in all cases.
Results: Patients were 24 to 56 yrs old (mean 40 yrs; M:F-3:2). 3/5 had SLE; 1/5 RA; 1/5 L.E prep + and ANA+. All had splenomegaly 232 -803gm (mean 421 gm). 4/5 exhibited histiocytic necrosis without acute inflammation similar to Kikuchi-Fujimoto disease. 4/5 showed extramedullary hematopoiesis. 1/5 showed florid follicular hyperplasia with little necrosis. Splenic involvement was focal to diffuse. The white pulp showed necrosis with karyorrhectic debris. Surrounding the necrotic areas were benign histiocytes and immunoblasts. Plasma cells were present; IgG4 was not increased. Hematoxylin bodies and CD123+ plasmacytoid dendritic cells were not identified. Stains for infectious organisms were negative. IHC Kappa and lambda showed no clonality in 4/4. EBER stained rare single cells in 4/4 cases tested. The 16S rDNA assay was negative (no amplification) in 2/4 cases and equivocal in 1/ 4 (1 in 7 blocks amplified).
Conclusions: Splenomegaly in autoimmune disease is rarely studied and is thought to be hyperplastic in most cases, but we present rare cases of histocytic necrosis in the spleen associated with autoimmune disease. The significance of the rare EBV positive cells in these cases, bystander or an intimate to the etiology of the splenomegaly, is uncertain. The significance of positivity in the 16SrDNA assay in one case is also uncertain and exposure to bacteria cannot be excluded.
Category: Techniques

Monday, March 19, 2012 1:00 PM

Poster Session II # 292, Monday Afternoon

 

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