Lymph node necrosis in systemic lupus erythematosus. A histopathological and immunohistochemical study of four cases

Clinicopathologic spectrum of necrotizing lymphadenitis

Background

Necrotizing lymphadenitis represents a group of diseases characterized by non-granulomatous inflammation and necrosis of the lymph node, caused by a variety of infective and inflammatory diseases, most common being Kikuchi-Fujimoto disease, acute Epstein Barr viral infection and systemic lupus erythematosis (1).

Objectives

To study the morphological features in lymph nodes in cases of necrotizing lymphadenitis, to correlate them with specific etiological conditions.Materials and methods-58 cases of necrotizing lymphadenitis were reviewed and categorized into different etiological sub types, i.e. acute EBV lymphadenitis, lupus lymphadenitis and the rest as Kikuchis lymphadenitis. Morphological features studied were presence of vascular proliferation, periadenitis, foamy macrophage, neutrophil and plasma cell infiltrate. Clinical follow up was done.

Results

62.2% of cases were Kikuchis lymphadenitis. Both lupus and Kikuchis had a female preponderance (78% and 62% respectively). Among the morphological parameters, plasma cell infiltration and vascular proliferation showed significant association with lupus lymphadenitis. Kikuchis and EBV lymphadenitis showed self-limiting course, with only 2 cases of Kikuchis developing recurrence .4 cases developed complications. All cases of lupus lymphadenitis needed long term therapy.

Conclusion

Kikuchis lymphadenitis is the most common cause of necrotizing lymphadenitis, followed by lupus and acute EBV lyphadenitis.Young females were commonly affected in the first 2 groups. It is worthwhile to classify the cases of necrotizing lymphadenitis into etiological subgroups as the prognosis and treatment differ (2). Among the morphological features studied, plasma cell infiltrate and vascular proliferation were significantly associated with lupus lymphadenitis, hence can be used to predict etiology.

Plasmacytoid Dendritic Cells Producing Interferon-α (IFN-α) and Inducing Mx1 Play an Important Role for CD4(+) Cells and CD8(+) Cells in Necrotizing Lymphadenitis

We confirmed the characteristic clinical features of necrotizing lymphadenitis (NEL) in 66 cases (23 male, 43 female) in Japan, which included high fever (38-40°), painful cervical lymphadenopathy (62/66, 93.9%), and leukopenia (under 4,000/mm(3)) (25/53, 47.2%), without seasonal occurrence, in a clinicopathological, immunohistochemical, electron microscopic serological study. Patient age varied from 3-55 years, and 72.7% (44/66) of patients were younger than 30 years. Histopathology of NEL was characterized by the presence of CD8(+) immunoblasts, CD123(+) cells (plasmacytoid dendritic cells; PDCs), histiocytes and macrophages phagocytizing CD4(+) apoptotic lymphocytes, but no granulocytes or bacteria. The number of PDCs and CD8(+) cells in lesions tended to increase with time, and PDCs tended to be larger and irregular in the lesions compared with the non-lesion tissue of the lymph nodes. In addition, PDCs showed no temporal morphological change in the lymph nodes. The number of CD4(+) cells in the lymph node lesions sharply decreased from the 2nd to the 4th week, and then tended to increase; however, CD4(+) cells gradually decreased with time in non-lesion tissue. PDCs may produce interferon-α (IFN-α), which induces Mx1 expression. Strong Mx1 immunoreactivity is indicative of IFN-α production. IFN-α induces transformation of CD8(+) cells into immunoblasts, as well as phagocytosis of apoptotic cells derived from CD4(+) cells by macrophages. Thus, PDCs may play an important role with immune cells, including CD8(+) and CD4(+) cells, in necrotizing lymphadenitis.

Distribution of Epstein-Barr Virus in Systemic Rheumatic Disease (Rheumatoid Arthritis, Systemic Lupus Erythematosus, Dermatomyositis) With Associated Lymphadenopathy: A Study of 49 Cases

Among systemic rheumatic diseases (SRDs), lymphadenopathy is frequently found in patients with rheumatoid arthritis (RA) and systemic lupus erythematous (SLE). Epstein-Barr virus (EBV)-associated lymphoproliferative disorders (LPDs) may occur in patients following methotrexate therapy for RA and dermatomyositis (DM). However, little is known about the distribution of EBV in reactive LPDs in patients with SRDs who had no history of methotrexate therapy. We analyzed 49 such patients (SLE=25, RA=23, DM=1) for the presence and distribution of EBV+ cells using Epstein-Barr virus (EBV)-encoded small RNA (EBER) specific in situ hybridization. A positive signal for EBERs was identified in 9 (SLE=5, RA=4) (18%) of 49 cases, and 3 main distribution patterns of EBER+ cells could be delineated: pattern A, more than 500 EBER-positive cells were located in the germinal centers as well as interfollicular area (SLE=2); pattern B, EBER + cells were located in a few germinal centers (RA=2); and pattern C, up to 100 EBER+ cells were located in the interfollicular area (SLE=3, RA=2). Recent EBV infection may be a cause of lymph node lesion in only 2 cases of patients with pattern A. However, the pathognomonic significance of pattern B and pattern C EBER+ cell distribution patterns still remains unclear. Our study indicates that the underlying immune deficits of patients with SRDs may also play an important role in the development of EBV-associated LPDs in SRDs, as previously suggested by several authors.

Histological diversity of reactive and atypical proliferative lymph node lesions in systemic lupus erythematosus patients

Localized or generalized lymphadenopathy, which may be associated with systemic symptoms such as fever, is frequently found in patients with systemic lupus erythematosus (SLE). Histologically, the lymph node lesion is characterized by varying degrees of coagulative necrosis with hematoxylin bodies or reactive follicular hyperplasia. The former histology is unique to SLE, but is rarely seen in biopsied specimens. In this review, we describe a histologic variation of SLE lymphadenopathy based on the findings of our own cases, and discuss several problems related to the differential diagnosis of various benign and malignant lymphoproliferative disorders (LPDs). Among 33 cases we encountered, 17 (51%) cases exhibited atypical LPDs: (i) reactive follicular hyperplasia with giant follicles (RFHGFs), 3 cases; (ii) histologic findings of Castleman's disease (CD), 5 cases ; (iii) atypical paracortical hyperplasia with lymphoid follicles (APHLFs), 7 cases; and (iv) atypical lymphoplasmacytic and immunoblastic proliferation (ALPIBP), 2 cases. This finding indicates that atypical LPDs frequently appear in SLE. Moreover, the majority of patients with atypical LPDs exhibited follicular hyperplasia (RFHGF, 3 cases; histologic findings of CD, 5 cases; and APHLF, 7 cases). Previously, follicular hyperplasia was usually considered a non-specific change and therefore has received little attention in the literature. However, the present review indicates that reactive follicular hyperplasia in lymph nodes from SLE occasionally poses serious problems in the differential diagnosis of various benign and malignant LPDs. The presence of numerous copies of Epstein-Barr virus was determined by in situ hybridization studies in only two (8%) of the 26 cases examined. As previously suggested, the absence of EBV, as determined by ISH studies, in the majority of LPDs associated with SLE indicates that EBV is not related to the lymphoproliferative process, and suggests that the underlying cause of the patient's lymphadenopathy may reside in the immune deficit of SLE in the majority of reactive and atypical LPDs associated with SLE.

Lupus lymphadenitis simulating Kikuchi's lymphadenitis in patients with systemic lupus erythematosus: a clinicopathological analysis of six cases and review of the literature

Kikuchi's disease (KD) or Kikuchi's lymphadenitis (KL) is a self-limiting disease mostly affecting the cervical lymph nodes of young individuals. Whether the reported cases of KL associated with systemic lupus erythematosus (SLE) were genuine KL or lupus lymphadenitis (LL) simulating KL in SLE patients is not clear. We analyzed six cases of KD-like lymphadenitis occurring in SLE patients and 12 reported cases to clarify the relationship between KL and SLE. We found that not all cases occurred simultaneously with SLE. Eight cases occurred either before or after SLE. These cases might have true KL independent of SLE with the exception of two cases that occurred after SLE, but the patients still had lupus activity. The 10 cases that coexisted with SLE most likely had LL rather than KL. This was supported by the immunohistochemical finding of sparse cytotoxic T cells in those lymph nodes in contrast to abundant cytotoxic T cells usually seen in a typical KL. We conclude that KL is not related to SLE, and KD-like lymphadenitis coexisting with SLE should be regarded as LL. Pathologists should be aware of the possibility that LL can mimic KL in patients with SLE, especially necrotizing-type KL.