Nonproliferative and Proliferative Lesions of the Rat and Mouse Hematolymphoid System.

The INHAND Project (International Harmonization of Nomenclature and Diagnostic Criteria for Lesions in Rats and Mice) is a joint initiative of the Societies of Toxicologic Pathology from Europe (ESTP), Great Britain (BSTP), Japan (JSTP), and North America (STP) to develop an internationally accepted nomenclature for proliferative and nonproliferative changes in rats and mice. The purpose of this publication is to provide a standardized nomenclature for classifying changes observed in the hematolymphoid organs, including the bone marrow, thymus, spleen, lymph nodes, mucosa-associated lymphoid tissues, and other lymphoid tissues (serosa-associated lymphoid clusters and tertiary lymphoid structures) with color photomicrographs illustrating examples of the lesions. Sources of material included histopathology databases from government, academia, and industrial laboratories throughout the world. Content includes spontaneous lesions as well as lesions induced by exposure to test materials. The nomenclature for these organs is divided into 3 terminologies: descriptive, conventional, and enhanced. Three terms are listed for each diagnosis. The rationale for this approach and guidance for its application to toxicologic pathology are described in detail below.

Impact of loss of NF-κB1, NF-κB2 or c-REL on SLE-like autoimmune disease and lymphadenopathy in Fas(lpr/lpr) mutant mice.

Defects in apoptosis can cause autoimmune disease. Loss-of-function mutations in the 'death receptor' FAS impair the deletion of autoreactive lymphocytes in the periphery, leading to progressive lymphadenopathy and systemic lupus erythematosus-like autoimmune disease in mice (Fas(lpr/lpr) (mice homozygous for the lymphoproliferation inducing spontaneous mutation)) and humans. The REL/nuclear factor-κB (NF-κB) transcription factors regulate a broad range of immune effector functions and are also implicated in various autoimmune diseases. We generated compound mutant mice to investigate the individual functions of the NF-κB family members NF-κB1, NF-κB2 and c-REL in the various autoimmune pathologies of Fas(lpr/lpr) mutant mice. We show that loss of each of these transcription factors resulted in amelioration of many classical features of autoimmune disease, including hypergammaglobulinaemia, anti-nuclear autoantibodies and autoantibodies against tissue-specific antigens. Remarkably, only c-REL deficiency substantially reduced immune complex-mediated glomerulonephritis and extended the lifespan of Fas(lpr/lpr) mice. Interestingly, compared with the Fas(lpr/lpr) animals, Fas(lpr/lpr)nfkb2(-/-) mice presented with a dramatic acceleration and augmentation of lymphadenopathy that was accompanied by severe lung pathology due to extensive lymphocytic infiltration. The Fas(lpr/lpr)nfkb1(-/-) mice exhibited the combined pathologies caused by defects in FAS-mediated apoptosis and premature ageing due to loss of NF-κB1. These findings demonstrate that different NF-κB family members exert distinct roles in the development of the diverse autoimmune and lymphoproliferative pathologies that arise in Fas(lpr/lpr) mice, and suggest that pharmacological targeting of c-REL should be considered as a strategy for therapeutic intervention in autoimmune diseases.

Immunoglobulin G4-related disease mimicking lymphoma in a Chinese patient.

Immunoglobulin G4-related disease (IgG4-RD) is a systemic disorder characterized by multiorgan fibrosis with IgG4-producing plasma cells, increased IgG4 serum concentration, and responsiveness to steroid therapy. IgG4-RD tends to form tumefactive lesions. As a result, patients are often suspected of having a malignancy such as lymphoma. In this article, a patient with IgG4-RD and the deep vein thrombosis who was initially suspected of lymphoma is reported. The 63-year-old man presented with painless salivary swelling and multi-lymphadenopathy, progressively swelling and pain in the left leg. Salivary biopsy showed IgG4+ plasma cells >50 per high-power field and IgG4+/IgG+ plasma cell ratio >40 %. The serum IgG4 level was 4.28 g/L (range 0.03-2.01 mg/dL). Ultrasonography showed that the inferior vena cava was partially occluded, and thrombosis in the left iliac vein. Computed tomography scan revealed plaque-like tissue surrounding the inferior vena cava and abdominal aortic, which is typical for the diagnosis of retroperitoneal fibrosis. The patient was effectively treated with corticosteroids, interventional therapy, and anticoagulant therapy which resulted in a reduction in the swelling of the lymph nodes and left leg. Patient with IgG4-RD and deep vein thrombosis is rare and could be misdiagnosed easily as malignant disease. Accurate diagnosis is critical for disease management.

Primary Sjögren's syndrome with chronic tubulointerstitial nephritis and lymphadenopathy mimicking IgG4-related disease.

We describe a 62-year-old woman with Sjögren's syndrome (SS) presenting with tubulointerstitial nephritis (TIN) and lymphadenopathy mimicking IgG4-related disease (IgG4-RD). Computed tomography revealed multiple swollen lymph nodes. Biopsy of the largest lymph node showed reactive lymphadenopathy with dense IgG4 positive plasma cell (IgG4 + PC) infiltration. Renal biopsy showed chronic plasma cell-rich TIN with IgG4 + PC infiltration. This case suggests that Immunoglobulin G4 immunostaining does not always support the diagnosis of IgG4-RD in the differential diagnosis between SS and IgG4-RD.

Rituximab for treating CD20+ prostate cancer with generalized lymphadenopathy: a case report and review of the literature.

A role for CD20 antibodies in treating prostate cancer has not yet been established. We report a case of advanced prostate cancer presenting with generalized lymphadenopathy that expressed CCR7 and CD20. CCR7 expression in prostate cancer has been previously reported only once; the expression of CD20 has not been reported before. Rituximab therapy was initiated in this case and resulted in a significant biochemical response. This unique metastatic and biochemical pattern may signify a distinct subtype of prostate cancer that may be amenable to treatment with anti-CD20 antibodies.

[IgG4-related disease, the new "great mimicker": report of one case]. / Enfermedad relacionada a IgG4, el nuevo "gran simulador": caso clínico.

Due to its multisystem involvement, IgG4 -related disease should be considered in the differential diagnosis of medical conditions such as lymphadenopathies, aortitis, serositis and retroperitoneal fibrosis. It shares features with other entities historically described as "great mimickers" such as syphilis, tuberculosis, sarcoidosis, and systemic lupus erythematosus. We report a 40 year-old male with recurrent effusive - constrictive pericarditis, lymphadenopathy and aortitis. The study revealed an inactive tuberculosis with negative cultures for acid fast bacilli. The patient had high serum levels of IgG4 and a mediastinal lymph node biopsy was consistent with IgG4 -related disease. The patient was treated with prednisone 40 mg/day with an excellent response.

Raised numbers of IgG4-positive plasma cells are a common histopathological finding in orbital xanthogranulomatous disease.

PURPOSE: To determine the relation of orbital xanthogranuloma with IgG4-related disease. METHODS: Retrospective consecutive case series over a period of 25 years. We searched our charts for histologically confirmed orbital xanthogranuloma. Patient files were reviewed for clinical and follow up data including presence or absence of systemic non-ophthalmic manifestations of IgG4 related disease. Slides were re-examined and histopathological classification was re-assessed. Sixteen cases of orbital xanthogranuloma were evaluated. Immunohistochemical stains for IgG and IgG4 were performed. Positive immunohistochemical staining required increased IgG4-positive plasma cells in the involved tissues scored as >50 per high-power field, with IgG4/IgG ratio >0.40. RESULTS: According to the criteria described above 8/16 (50%) cases showed increased numbers of IgG4-positive plasma cells in the specimens. Two of these patients may have had signs of systemic disease. CONCLUSION: Raised numbers of IgG4-positive plasma cells are a common finding in histopathological specimens of xanthogranulomatous disease of the orbit and are often not indicative for IgG4 related systemic disease.

The spectrum of IgG4-related disease in the abdomen and pelvis.

OBJECTIVE: IgG4-related disease was not recognized as a specific clinical entity until 2003 when extrapancreatic lesions were reported in patients with autoimmune pancreatitis. IgG4-related disease is characterized by elevated serum IgG4 levels and infiltration of the target organ by IgG4-positive plasma cells. The complete gamut of visceral involvement is still being outlined. The purpose of this article is to highlight the plethora of lesions under the spectrum of IgG4-related disease of the abdomen and pelvis, describe their imaging appearances on multimodality cross-sectional imaging, and discuss the differential diagnoses. CONCLUSION: It is important for radiologists to recognize the multiorgan involvement and few classic features of IgG4-related disease that often tend to simulate malignancy.

Clinical significance of complement as a biomarker of disease activity in 4 cases of IgG4-related disease with retroperitoneal fibrosis.

Hypocomplementaemia is frequently observed in IgG4-related diseases, however the clinical significance is unclear. We describe herein the clinical courses of 4 patients with IgG4-related disease with hypocomplementaemia. Our cases showed autoimmune pancreatitis, retroperitoneal fibrosis, Mikulicz's disease, interstitial lung disease, lymphadenopathy and mesenteric fibrosis around the aorta. A decrease in serum complement preceded deterioration of the disease and clinical improvement was observed in accordance with normalisation of serum complement. These clinical courses suggest that serum complement is a biomarker of the disease activity.

A case of Epstein-Barr virus-related lymphadenopathy mimicking the clinical features of IgG4-related disease.

We report an intriguing case of Epstein-Barr virus (EBV)-related multiple lymphadenopathy that clinically mimics immunoglobulin G4-related disease (IgG4-RD). A 72-year-old woman presented with a history of asthma attacks, systemic lymphadenopathy, hypergammaglobulinemia, proteinuria, and an elevated level of serum IgG4, leading to a possible diagnosis of IgG4-RD based on current comprehensive diagnostic criteria. However, a percutaneous kidney biopsy specimen showed mild mesangial proliferative glomerulonephritis with focal membranous transformation, and there was no interstitial lesion or lymphocyte infiltration. Cervical lymph node biopsy demonstrated follicular hyperplasia associated with prominent lymphoplasmacytic infiltration in the interfollicular area. However, only a few IgG4-positive plasma cells were present. An in situ hybridization study demonstrated many EBV-infected lymphocytes in the germinal center as well as in the interfollicular area. This case illustrates the diversity of conditions associated with elevated levels of serum IgG4 and the necessity for tissue biopsy when diagnosing IgG4-RD.

Histopathological findings in 29 lymph node biopsies with increased IgG4 plasma cells.

IgG4-related sclerosing disease encompasses a family of disorders associated with increased numbers of IgG4 plasma cells and mass forming lesions in various tissues. Lymphadenopathy is a common finding, seen in up to 80% of cases. In the largest series of cases to date, we describe histologic, immunohistochemical, special stain and flow cytometric findings in 29 cases of enlarged lymph nodes with increased IgG4 plasma cells. Lymph node biopsies showed all resection specimens; no needle core biopsies of tissue were evaluated. Cases were considered to have increased numbers of IgG4 plasma cells using the histological criteria outlined by Cheuk and Chan (2010): IgG4 plasma cells >50 cells in a high-power field and >40% of IgG-positive plasma cells positive for IgG4. Additionally, increased intrafollicular plasma cells were a common finding. The lymph nodes showed a variety of reactive histological features including follicular hyperplasia, progressive transformation of germinal centers, interfollicular expansions, variable degrees of fibrosis, increased histiocytes and occasionally an appearance similar to that of plasma cell Castleman disease.

Primary hyperparathyroidism: fifth parathyroid intrathymic adenoma in a young patient.

The clinical case described in this paper deals with a young female patient affected by primary hyperparathyroidism caused by an ectopic parathyroid adenoma of a supernumerary intrathymic parathyroid. The patient had hypercalcemia, in association with increased levels of parathormone, but was otherwise asymptomatic. Genetics tests for mutation of the MEN1, HRPT2, and CaSR genes were negative. She therefore underwent laboratory and instrumental tests but localization results in the neck were negative--only an intrathymic nodule was visualized. The complete surgical ablation of the thymus was conducted, which highlighted a nodule that, at histological examination, was shown to be an adenoma of a fifth parathyroid gland. The existence of a fifth, hyperfunctioning, intrathoracic parathyroid appears to be a rare cause of primary juvenile sporadic hyperparathyroidism. This peculiar clinical case could be of interest in similar cases evaluated by other surgeons.

Whole-blood interferon-gamma release assay for diagnosis of tuberculous lymphadenitis.

Tuberculosis remains a major problem for much of the world. Tuberculous lymphadenitis is the most common type of extrapulmonary tuberculosis, although a difficult invasive procedure is required for its diagnosis. We evaluated the usefulness of the whole-blood interferon-gamma release assay (IGRA) for diagnosis of tuberculous lymphadenitis. From January 2008 to October 2010, 108 patients underwent lymph node biopsy and the IGRA concurrently in Wonju Christian Hospital, Yonsei University Wonju College of Medicine. Among the patients, 27 were diagnosed with tuberculous lymphadenitis and 81 were diagnosed with non-tuberculous lymphadenitis. The diagnostic performances of the IGRA were evaluated. The median patient age was 33 years (interquartile range [IQR] 23.5 to 48 years), and 28 (25.9%) patients were male. No patient was administered immunosuppressive agents such as high-dose steroids or underwent chemotherapy within 90 days before the IGRA test. The IGRA was positive in 25 of 27 patients with tuberculous lymphadenitis and in 13 of 81 patients with non-tuberculous lymphadenopathy. Therefore, the sensitivity of IGRA was 92.6% (95% CI, 82.0 to 100), and the specificity was 80.2% (95% CI, 71.4 to 89.1). In the patients with positive IGRA results, the INF-γ concentration was significantly higher in the patients with tuberculous lymphadenitis compared to that in the patients without tuberculous lymphadenitis (15.58 [IQR 6.87 to 45.10] IU/mL versus 0.97 [IQR 0.65 to 2.41] IU/mL, p < 0.001). In conclusion, the IGRA is helpful for the diagnosis of tuberculous lymphadenitis.

The surface morphology of human B lymphocytes as revealed by immunoelectron microscopy.

Surface immunoglobulins (sIg) were detected on human lymphocytes by immunoelectron microscopy with peroxidase-conjugated antibodies. Blood, marrow, and thymus cells from normal individuals and patients with lymphoproliferative disorders were examined. Samples were fixed before exposure to specific reagents. Normal lymphocyts with detectable sIg, i.e. B lymphocytes, were characterized by a villous surface; nonlabeled blood lymphocytes and thymocytes were smooth cells. Intermediate cells were also found which in sections appeared moderately villous and labeled, thus identified as B lymphocytes. Further evidence for a relationship between villous surface and sIg was given by the finding of a few lymphocytes with polar concentration of labeled microvilli. In chronic lymphocytic leukemia patients, most cells exhibited a villous surface with parallel variations of the number of microvilli and of anti-immunoglobulin-binding capacity. However, some labeled smooth blastic cells were also observed. On the other hand, abnormal lymphocytes from Sézary's syndrome which could exhibit segments of villous membrane had no detectable sIg. This study confirms that in most cases human B lymphocytes have a characteristic surface appearance and that the detection of sIg in normal lymphocytes correlates with the presence of microvilli.

Proangiogenic cytokines vascular-endothelial growth factor and basic fibroblst growth factor in childhood lymphadenopathy.

Increased angiogenesis is observed both in the inflammatory and in the neoplasmatic tissue. The aim of the study was to assess the diagnostic significance of serum concentration of vascular-endothelial growth factor (sVEGF) and basic fibroblast growth factor (sbFGF) in the various forms of lymphadenopathy in children. Ninety-four children with lymphadenopathy were studied: group A, 52 patients with lymphadenitis; group B, 42 patients with lymphomas. Group B was divided into subgroups: B(P), children with lymphomas in peripheral lymph nodes and B(M), children with lymphomas in peripheral lymph nodes and mediastinal tumor. The healthy control group was 20 children. Using enzyme-linked immunosorbent assays the authors quantified VEGF and bFGF in serum of healthy children and of children with lymphadenopathy. The sVEGF in group A was significantly higher than controls (313.8 versus 44.6 pg/mL; P <.05) and in group B was 633.4 pg/mL and was significantly higher than controls (P <.0001). The sVEGF and bFGF in group A versus subgroup B(P) were significantly lower (P(VEGF) <.05, P(bFGF) <.05), and sVEGF in subgroup B(P) versus B(M) was significantly lower (P <.05). These results show that the evaluation of serum VEGF concentration might be useful as noninvasive diagnosis of some chronic peripheral lymphadenopathies in children.

The platelet defect in leukemia. Platelet ultrastructure, adenine nucleotide metabolism, and the release reaction.

The ultrastructure and adenine nucleotide metabolism of platelets from patients with acute leukemia were studied to elucidate possible mechanisms for the platelet dysfunction observed in this clinical setting. Nonstimulated (resting) platelets from leukemic patients varied greatly in size; exhibited marked variation in the number of alpha granules present per cell; had poorly delineated circumferential bands of microtubules; and often grossly dilated open channel systems or cytoplasmic vacuolization. The intracellular concentrations of ATP and ADP were significantly below normal, and the specific radioactivity of ATP and ADP of nonstimulated platelets in leukemia was equivalent to or exceeded that seen in stimulated normal platelets. Addition of ADP or collagen to platelets from leukemic patients was followed by retarded and incomplete shape change, delayed and incomplete centripetal migration of subcellular organelles, impaired degranulation, and the formation of loose aggregates composed of relatively few platelets. Stimulation of "leukemic" platelets with collagen led to the release of significantly subnormal amounts of ATP and ADP and no significant change in the specific radioactivity of the intracellular nucleotides. In contrast to the results in normal platelets, the conversion of ATP to inosine monophosphate and hypoxanthine in platelets in leukemia failed to increase significantly with collagen stimulation. The results indicate that abnormalities exist in the storage pool of adenine nucleotides and the release mechanism of platelets in acute leukemia. These defects appear to contribute to an impairment in the release reaction in these platelets. Many of the ultrastructural and metabolic defects seen in acute leukemia occur in platelets in preleukemia.

Effect of cardiac lymph flow obstruction on cardiac collagen synthesis and interstitial fibrosis.

The effect of chronic cardiac lymphatic obstruction on the myocardial synthesis of collagen type I and III was investigated in a rabbit model. In the lymphatic obstruction group (n=16), plasma C-terminal propeptide type I procollagen (PICP) and N-terminal propeptide type III procollagen (PIIINP) were elevated at 7, 14 and 30 days after the operation (p<0.05). The elevated PICP and PIIINP returned to the pre-operation values 60 days after the operation. The myocardial expression of collagen type I and III mRNA were also enhanced in the lymphatic flow obstruction group. Plasma PICP, PIIINP and myocardial collagen type I and III mRNA remained unchanged in the control group (n=16). We concluded that chronic obstruction of cardiac lymph flow leads to enhanced myocardial collagen synthesis in rabbits. The enhanced collagen synthesis starts within seven days after lymphatic obstruction and subsides after 60 days.

Nontuberculous mycobacterial infection with concurrent IgG4-related lymphadenopathy.

Disseminated nontuberculous mycobacteria (NTM) infection with concurrent IgG4-related lymphadenopathy has not been reported. We described a patient with neutralizing autoantibodies to interferon-gamma (IFN-γ) and elevated levels of serum IgG4 presenting with generalized lymphadenopathy and reactive dermatosis. Histologically, lymph nodes (LNs) showed effaced nodal architecture with polymorphic infiltrates, mimicking angioimmunoblastic T-cell lymphoma. Both the absolute number and the ratio of IgG4+ plasma cells to IgG+ plasma cells were increased. Mycobacterium abscessus was isolated from cultures of LNs, and demonstrated by polymerase chain reaction-restriction fragment length polymorphism. The skin biopsy showed neutrophilic dermatosis, consistent with Sweet syndrome. The patient met the criteria of both adult-onset immunodeficiency syndrome and IgG4-related lymphadenopathy. This case provides evidence of disseminated NTM infection with concurrent type III IgG4-related lymphadenopathy in the patient with anti-IFN-γ autoantibodies.