Endosalpingiosis Is Negative for GATA3.

CONTEXT.­: Endosalpingiosis is a benign Müllerian inclusion that can mimic metastatic low-grade mammary carcinoma, particularly when encountered in axillary lymph nodes excised for breast cancer staging. Immunohistochemistry can be useful in histologically ambiguous cases, and a targeted immunopanel should include a marker of gynecologic tract origin and a marker of mammary origin. GATA3 is a sensitive immunomarker for breast carcinoma, but the immunoreactivity of GATA3 in endosalpingiosis has not been systematically evaluated. OBJECTIVE.­: To evaluate whether GATA3 immunohistochemistry could be used to differentiate endosalpingiosis from metastatic mammary carcinoma. DESIGN.­: Whole slide sections of 15 cases of endosalpingiosis involving nonneoplastic tissues were subjected to GATA3 immunohistochemistry. Nuclear GATA3 labeling was scored as percentage and intensity labeling, with any labeling considered positive; GATA3 labeling was recorded in all cells present in the sections. RESULTS.­: Half (47%, n = 7 of 15) of the endosalpingiosis cases involved lymph nodes (2 axillary, 5 pelvic) and half (53%, n = 8 of 15) involved pelvic organs or soft tissue (3 myometrial, 2 paratubal, 2 periadnexal soft tissue, and 1 pelvic sidewall). GATA3 immunohistochemistry was negative in all cases of endosalpingiosis, with intact, positive control labeling in lymphocytes. The benign fallopian tube epithelium present on the sections of paratubal endosalpingiosis displayed focal (<5%), weak labeling for GATA3, specifically within the ciliated and secretory cells. CONCLUSIONS.­: These findings support the diagnostic utility of GATA3 immunohistochemistry and its use in a targeted immunopanel to resolve the differential diagnosis of metastatic low-grade mammary carcinoma (GATA3+) and nodal endosalpingiosis (GATA3-).

Analysis of mTOR pathway expression in lymphatic malformation and related diseases.

The mammalian target of rapamycin (mTOR) inhibitor sirolimus is an effective treatment for difficult-to-treat lymphatic anomalies. However, little is known about the expression of mTOR pathway components in lymphatic anomalies. Here we investigated the expression pattern of mTOR pathway components and their phosphorylated forms (mTOR, p-mTOR, 4EBP1, p-4EBP1, S6K1 and p-S6K1) in normal lymphatic vessels and lymphatic anomalies using immunohistochemistry. We studied 18 patients of lymphatic anomalies, including lymphatic malformation (LM, n = 14), Kaposiform lymphangiomatosis (KLA, n = 2) and Kaposiform hemangioendothelioma (KHE, n = 2). Normal lymphatic vessels expressed 4EBP1, S6K1 and p-S6K1, but not p-4EBP1, mTOR or p-mTOR. The mTOR was detected in all lymphatic anomalies, whereas its activation form p-mTOR was detected in half cases of KLA and KHE but not in LM. All lymphatic anomalies expressed S6K1 and its activated form p-S6K1. The expression of 4EBP1 was also found in all lymphatic anomalies, but its activation was detected in approximately half of them. The activation of mTOR was seen in tumor (KLA and KHE) but not in malformation (LM), whereas the activation of S6K1 and 4EBP1 was seen in all and half of lymphatic anomalies, respectively.

Flow immunophenotyping of benign lymph nodes sampled by FNA: Representative with diagnostic pitfalls.

BACKGROUND: Fine-needle aspiration with flow cytometry (FNA-FC) is routinely used in the evaluation of lymph nodes suspicious for lymphoma, yet data comparing immunophenotype distributions and outliers in benign lymph nodes sampled by fine-needle aspiration (FNA) versus excision are lacking. METHODS: Flow cytometry data from 289 benign lymph node FNA cases were assessed for the overall antigen distribution, with a focus on outliers relevant to the diagnosis of lymphoma. Distributions and outlier proportions were compared with those of a separate cohort of 298 excisional biopsies. RESULTS: Compared with excisional biopsies, FNA specimens overrepresented CD3+ events (72% vs 63%), underrepresented CD19+ events (22% vs 29%), and had 25% fewer large cell-gated events. Normalized antigen distributions in FNA were equivalent to those in excisional biopsy. Twenty-three percent of FNA-FC cases exhibited an outlier, including a skewed kappa:lambda light-chain ratio, increased CD5+ or CD10+ B-cell events, a skewed CD4:CD8 ratio, and increased CD7 loss on T cells, with no significant differences in frequency or type in comparison with excisional specimens. Outliers for the light-chain ratio and T-cell antigens were enriched among older patients and included patients with a variety of autoimmune/rheumatologic conditions. CONCLUSIONS: Benign lymph node FNA yields flow immunophenotypes remarkably similar to those from excisional biopsies. Outlier flow immunophenotypes are identified in benign lymph nodes sampled by FNA at a frequency similar to that with excisional biopsies. Older patients, who have a higher baseline risk of lymphoma, are more likely to exhibit lymphoma-mimicking outliers such as a light-chain predominance on B cells and skewed CD4:CD8 ratios or increased CD7 loss on T cells, and they warrant additional diagnostic caution.

Emerging Roles for VEGF-D in Human Disease.

Blood vessels and lymphatic vessels are located in many tissues and organs throughout the body, and play important roles in a wide variety of prevalent diseases in humans. Vascular endothelial growth factor-D (VEGF-D) is a secreted protein that can promote the remodeling of blood vessels and lymphatics in development and disease. Recent fundamental and translational studies have provided insight into the molecular mechanisms by which VEGF-D exerts its effects in human disease. Hence this protein is now of interest as a therapeutic and/or diagnostic target, or as a potential therapeutic agent, in a diversity of indications in cardiovascular medicine, cancer and the devastating pulmonary condition lymphangioleiomyomatosis. This has led to clinical trial programs to assess the effect of targeting VEGF-D signaling pathways, or delivering VEGF-D, in angina, cancer and ocular indications. This review summarizes our understanding of VEGF-D signaling in human disease, which is largely based on animal disease models and clinicopathological studies, and provides information about the outcomes of recent clinical trials testing agonists or antagonists of VEGF-D signaling.

Impaired PIEZO1 function in patients with a novel autosomal recessive congenital lymphatic dysplasia.

Piezo1 ion channels are mediators of mechanotransduction in several cell types including the vascular endothelium, renal tubular cells and erythrocytes. Gain-of-function mutations in PIEZO1 cause an autosomal dominant haemolytic anaemia in humans called dehydrated hereditary stomatocytosis. However, the phenotypic consequence of PIEZO1 loss of function in humans has not previously been documented. Here we discover a novel role of this channel in the lymphatic system. Through whole-exome sequencing, we identify biallelic mutations in PIEZO1 (a splicing variant leading to early truncation and a non-synonymous missense variant) in a pair of siblings affected with persistent lymphoedema caused by congenital lymphatic dysplasia. Analysis of patients' erythrocytes as well as studies in a heterologous system reveal greatly attenuated PIEZO1 function in affected alleles. Our results delineate a novel clinical category of PIEZO1-associated hereditary lymphoedema.

Desmoglein 3 and p40 immunoreactivity in neoplastic and nonneoplastic thymus: a potential adjunct to help resolve selected diagnostic and staging problems.

The potential usefulness of the squamous markers p40 and desmoglein 3 (DSG-3) for the diagnosis and staging of selected thymic lesions is uncertain. We investigated their expression and distribution pattern in 66 thymomas, 12 thymic squamous carcinomas, 6 undifferentiated thymic carcinomas, 5 hyperplastic thymi, and 5 normal thymi. p40 nuclear and DSG-3 cytoplasmic/membranous immunoreactivity in greater than or equal to 10% of thymic epithelial cells was interpreted as positive, and DSG-3 distribution pattern was classified as organotypic and nonorganotypic. All nonneoplastic thymic tissues, 100% of thymic squamous carcinomas, 97% of thymomas, and 50% of undifferentiated thymic carcinomas were positive for p40. Expression of p40 in almost all thymomas and in 50% of undifferentiated carcinomas that lacked squamous features suggests that p40 is not a good marker for the diagnosis of thymic squamous carcinoma. All normal and hyperplastic thymi, 51.5% of thymomas, and 0% of thymic squamous carcinomas expressed DSG-3 in an organotypic pattern, and 13.6% of thymomas and 83% of thymic squamous carcinomas were DSG-3 positive in a nonorganotypic pattern. Findings suggest that nonorganotypic DSG-3 expression favors the diagnosis of squamous cell carcinoma over thymoma. In 26 (60.5%) of the 43 cases where neoplastic and nonneoplastic thymus were present on the same slide, the presence/absence or distribution pattern of DSG-3 immunoreactivity was different in the 2 components, suggesting that this marker can be helpful in staging thymomas with incomplete encapsulation. The presence of DSG-3-positive and DSG-3-negative thymomas raises the possibility that these tumors may originate from 2 different types of thymic epithelial cells.

E proteins in lymphocyte development and lymphoid diseases.

As members of the basic helix-loop-helix (bHLH) family of transcription factors, E proteins function in the immune system by directing and maintaining a vast transcriptional network that regulates cell survival, proliferation, differentiation, and function. Proper activity of this network is essential to the functionality of the immune system. Aberrations in E protein expression or function can cause numerous defects, ranging from impaired lymphocyte development and immunodeficiency to aberrant function, cancer, and autoimmunity. Additionally, disruption of inhibitor of DNA-binding (Id) proteins, natural inhibitors of E proteins, can induce additional defects in development and function. Although E proteins have been investigated for several decades, their study continues to yield novel and exciting insights into the workings of the immune system. The goal of this chapter is to discuss the various classical roles of E proteins in lymphocyte development and highlight new and ongoing research into how these roles, if compromised, can lead to disease.

Is pneumatosis cystoides intestinalis gas-distended and ruptured lymphatics? Reappraisal by immunohistochemistry.

CONTEXT: Pneumatosis cystoides intestinalis (PCI) is a condition with multiple gas-filled cysts within the bowel wall, associated with diverse background diseases. Its pathogenesis is still a mystery. Some previous observations scattered in the literature have suggested an association of the cystic spaces in PCI with the lymphatics. OBJECTIVE: To further investigate whether PCI results from the ballooning of gas-filled lymphatic channels. DESIGN: We did immunostaining of podoplanin, a mucoprotein preferentially expressed in lymphatic endothelial cells, in 13 cases (8 men, 5 women; age range, 18-80 years) of PCI. Ten cases were diagnosed in resected segments of bowel and 3 in biopsies. Pneumatosis was seen in the right side of the colon (9 cases), transverse colon (1 case), sigmoid colon (1 case), and small bowel (2 cases). In addition, immunostaining for CD31, calretinin, WT1, CD68, smooth muscle actin, desmin, vimentin, and cytokeratins was also performed for comparison and correlation. RESULTS: A strong immunopositivity of podoplanin was seen in a condensed linear structure in the pericystic interstitium in 100% of the cases, but was not seen in the overlying giant and flat cells that were all CD68-positive histiocytes. Meanwhile, the podoplanin-expressing structure was negative for calretinin and WT1, which ruled out the possible mesothelial origin. There were coexistent variable immunopositivity of smooth muscle actin, which suggests an admixture of myofibroblasts. These findings indicated that the PCI cases were gas-distended lymphatics with the lymphatic epithelium ruptured and embedded in the reactive histiocytes and giant cells. CONCLUSION: Our findings support the lymphatic theory about the pathogenesis of PCI.

Clinical features of de novo CD25-positive follicular lymphoma.

CD25 expression in follicular lymphoma (FL) has not yet been investigated. Eighty-five patients with newly diagnosed FL were retrospectively evaluated. On two-color flow cytometric analysis, CD25 was detected on CD19 + and CD20 + lymphoma cells. CD25 expression in FL tended to be higher than in reactive lymphadenopathy, but was lower than in diffuse large B-cell lymphoma. Patients with CD25 + FL (n = 12) showed clinical features of elevated soluble interleukin-2 receptor (IL-2R) levels, B symptoms and an advanced age compared with CD25 - FL (n = 73). The overall response rate (ORR), progression-free survival (PFS) and overall survival (OS) in patients with CD25 + FL were significantly inferior to those with CD25 - FL (ORR, 60 vs. 93%; 2-year PFS, 32 vs. 80.3%; 6-year OS, 47.4 vs. 85.9%, respectively). Multivariate analysis demonstrated that CD25 positivity is an independent prognostic factor for PFS and OS in FL. CD25 + FL may constitute a distinct subgroup associated with aggressiveness and an inferior prognosis.

[Lymphatic endothelium in certain conditions].

Presented herein is a review of the literature data concerning the structural and functional peculiarities of the endothelium of the lymphatic and blood vessels. The authors consider the current state of the art of the problem regarding dysfunction of lymphatic endothelium dysfunctions developing in various diseases, as well as in the process of ontogenesis, pointing out an important role of impaired processes of lymphangiogenesis, underlying the development of diseases of the lymphatic system. The authors also assess administration of quercetine in treatment for chronic venous insufficiency, followed by suggesting a possible mechanism of its positive action consisting ina decrease in the oedema at early stages of lymphoedema.

Intranodular clusters of activated cells with T follicular helper phenotype in nodular lymphocyte predominant Hodgkin lymphoma: a pilot study of 32 cases from Finland.

In nodular lymphocyte predominant Hodgkin lymphoma (NLPHL), little is known about the presence of intranodular clusters of cytologically activated lymphoid cells producing a moth-eaten pattern histologically. This pilot study of 32 NLPHL cases from Finland ascertained (1) the frequency of the intranodular clusters of activated lymphoid cells, (2) the immunophenotype of the activated cells, (3) the size and immunophenotype of the rosetting cells, and (4) the clinical significance of the activated cells. Histologically, intranodular clusters of activated cells produced a moth-eaten pattern in 100% (32 cases; subtle in 62.5%, overt in 37.5%). In immunostains, activated cells in subtle clusters (20 cases) were very difficult to identify. Twelve cases had overt clusters of activated cells, which were positive with CD3, CD4, PD1, CXCL13 (T follicular helper [T(FH)] phenotype), but rarely with Ki-67 and BCL2. Most activated rosetting cells had the same immunophenotype as the nonrosetting cells, except for CXCL13. Clinical presentation for all 32 Finnish patients was distinctive: 97% men, 97% with peripheral lymphadenopathy and 35.5% with stage III/IV disease. Only 22% relapsed; 97% were in remission. There was no significant clinical difference between cases with overt and subtle clusters. Intranodular activated TFH cells in NLPHL appeared to be nonproliferating and not long-living, and they were not associated with any adverse clinical outcome. Although most activated cells were TFH cells, it seemed that they were unable to increase the number of malignant cells. The pathogenetic role of the intranodular activated TFH and the small T cells in NLPHL needs further investigation.

Peripheral lymphadenopathy as the initial manifestation of malignant mesothelioma in a child.

Peripheral lymphadenopathy is a rare presentation in malignant mesothelioma. We describe a unique case of malignant mesothelioma arising in an 11-year-old boy, for whom peripheral lymphadenopathy was the initial manifestation of the disease. The final diagnosis was confirmed by a broad panel of immunohistochemical markers. Literature review disclosed only 2 cases in childhood that initially presented with peripheral lymphadenopathy. Pathologists should be aware of this rare biologic behavior of malignant mesothelioma to reach the correct and prompt diagnosis.

Benign lymphadenopathies.

Benign lymphadenopathy is a common biopsy finding, and may often be confused with malignant lymphoma. It may be separated into major morphologic patterns, each with its own differential diagnosis with certain types of lymphoma. Most cases of reactive follicular hyperplasia is easy to diagnosis, but some cases may be confused with follicular lymphoma, but key morphologic, immunohistochemical, and molecular findings may usually distinguish between the two, particularly assessment of bcl-2 staining. Molecular studies to demonstrate B-cell clonality, as well as the t(14;18), may also be of great use in difficult cases. IgG4-associated sclerosing disease is discussed, as one recently described example of a specific type of reactive follicular hyperplasia in which the etiology may be suggested based on pathologic studies. While overlapping with the other types of hyperplasia, a high index of suspicion as well as IgG and IgG4 immunostains will help raise the possibility of the diagnosis that can be confirmed by further clinical studies. Reactive paracortical/interfollicular hyperplasia is another pattern of reactive hyperplasia, which may easily be confused with Hodgkin and non-Hodgkin lymphoma, particularly T-cell lymphoma. Epstein-Barr virus-associated infectious mononucleosis is an example of reactive paracortical/interfollicular hyperplasia, which may often simulate a malignant lymphoma. Attention to clinical findings, as well as a combination of immunohistochemical stains and in situ hybridization studies for Epstein-Barr early RNA (EBER) will usually allow a definitive diagnosis. In addition, lymph nodes with extensive necrosis may simulate malignant lymphoma. Kikuchi necrotizing histiocytic lymphadenitis is an example of a benign process with extensive necrosis, which may easily be confused with non-Hodgkin lymphoma. Clinical and morphologic features, particularly the presence of abundant karyorrhectic debris along with a paucity of granulocytes, as well as immunohistochemical studies to rule out lymphoma, are most helpful in establishing the correct diagnosis.

Accumulation of tissue macrophages and depletion of resident macrophages in the diabetic thymus in response to hyperglycemia-induced thymocyte apoptosis.

AIMS: We investigated the dynamics and morphology of thymus macrophages in response to thymus involution caused by hyperglycemia. Thymus is an organ affected early and dramatically after the onset of diabetes, losing most of the thymocyte populations but diabetes's impact on the components of the thymus stroma is largely unknown. METHODS: Rats were injected with streptozotocin and thymus weight, body weight, and glycemia were measured at various time points. The dynamics and morphology of macrophages in the diabetic thymus were investigated by histology, immunohistochemistry, qPCR, electron microscopy and flow cytometry. RESULTS: In hyperglycemic animals the involuting thymus is gradually infiltrated by tissue macrophages (ED1-positive) and depleted of resident macrophages (ED2-positive). While ED1 positive macrophages are scattered in both cortex and medulla the ED2 positive ones are limited to the cortex and cortico-medullary junction. CD4+CD11b+macrophages also accumulate. The TUNEL reaction that detects the degradation of the DNA from apoptotic thymocytes in the macrophages is enhanced. The thymic macrophages enlarge and accumulate lipid vacuoles and apoptotic bodies. qPCR measurements of the expression of macrophage markers showed a persistent increase in the diabetic thymus after the injection of streptozotocin. CONCLUSIONS: Thymus involutes rapidly and persistently after the onset of hyperglycemia because of the elevated apoptosis in the thymocytes. Tissue macrophages accumulate in the thymus and the resident macrophages decrease. This results in an overall increase in macrophage activity in the diabetic thymus in response to the elevated apoptosis of thymocytes produced by hyperglycemia.

Lymphadenopathy of IgG4-related disease: an underdiagnosed and overdiagnosed entity.

Lymphadenopathy is a common occurrence in IgG4-related disease; it can appear before, concurrent with, or after the diagnosis of this disease, which is characterized by tumefactive sclerosing inflammatory lesions predominantly affecting extranodal sites, such as the pancreas, salivary gland, and lacrimal gland. Although multiple lymph node groups are commonly involved, constitutional symptoms are absent. The lymph nodes can show a broad morphologic spectrum, including multicentric Castleman disease-like (type I), follicular hyperplasia (type II), interfollicular expansion (type III), progressive transformation of germinal centers (type IV), and inflammatory pseudotumor-like (type V). All are characterized by an increase in IgG4+ plasma cells (>100 per high power field) and IgG4/IgG ratio (>40%). IgG4-related lymphadenopathy is both an underdiagnosed and overdiagnosed entity. The former is because of the fact that this entity has not been characterized until recently, while the latter results from pathologists' enthusiasm in diagnosing "new" entities and the lack of specificity of the morphologic and immunophenotypic features of IgG4-related lymphadenopathy. It is prudent to render this diagnosis only for patients with known IgG4-related disease or in the presence of corroborating clinical and laboratory findings (such as elderly men, systemic lymphadenopathy, elevated serum IgG4, IgG, and IgE but not IgM and IgA, and low titers of autoantibodies). Outside these circumstances, a descriptive diagnosis of "reactive lymphoid hyperplasia with increased IgG4+ cells" accompanied by a recommendation for follow-up will be appropriate because IgG4-related disease will likely ensue only in a minority of such patients.

Follicular peripheral T-cell lymphoma expands the spectrum of classical Hodgkin lymphoma mimics.

Epstein-Barr virus (EBV)-infected B cells with Reed-Sternberg-like cell (RS) features may occur in peripheral T-cell lymphomas (PTCLs), especially in angioimmunoblastic T-cell lymphoma. Here, we report 5 patients presenting with lymphadenopathy whose first biopsies demonstrated nodular lymphoid proliferations containing scattered CD30+, CD15+, EBV+ Hodgkin and Reed-Sternberg-like cells, which led to an initial diagnosis of lymphocyte-rich classical Hodgkin lymphoma. However, the uncommon clinical features and/or the occurrence of relapse as PTCL prompted review of the biopsies with expanded immunohistologic and molecular studies and revision of the diagnoses to follicular variant of PTCL (F-PTCL). All cases had atypical small to medium-sized CD3+ T cells that expressed CD10 (4/5) and the follicular helper T-cell (TFH) antigens BCL6, PD1, CXCL13, and ICOS. All demonstrated clonal T cells with a similar pattern in multiple samples from 4 patients. In 2 cases, flow cytometry demonstrated circulating lymphocytes with an abnormal sCD3+, CD4+, ICOS+ immunophenotype. Two patients had a skin rash at presentation, and 1 had B symptoms. Two of the 4 patients treated with polychemotherapy are alive at 3 and 6 years after first diagnosis. These cases highlight how some F-PTCLs may closely mimic lymphocyte-rich classical Hodgkin lymphoma requiring careful assessment of the T cells before rendering the latter diagnosis. The functional properties of TFH cells might lead to the presence of EBV-positive B blasts with RS-like features in TFH-derived PTCL such as angioimmunoblastic T-cell lymphoma and F-PTCL.

Rheumatoid lymphadenopathy with abundant IgG4(+) plasma cells : a case mimicking IgG4-related disease.

Immunoglobulin (Ig) G4-related disease is a recently confirmed clinical entity with several unique clinicopathological features. Here we report a case of rheumatoid lymphadenopathy mimicking IgG4-related disease. The patient was a 63-year-old woman who had been treated for rheumatoid arthritis (RA) for six years. The patient noted cervical lymphadenopathy. Upon radiological examination, systemic lymphadenopathy was detected, and enlarged right brachial lymph node biopsy was performed. Histologically, the lymph node showed marked follicular hyperplasia and interfollicular plasmacytosis without eosinophil infiltration. Although the histological findings were compatible with rheumatoid lymphadenopathy, numerous plasma cells were IgG4(+) (IgG4(+)/IgG(+) plasma cell ratio > 50%). However, laboratory findings revealed elevation of C-reactive protein level, polyclonal hyper-γ-globulinemia, anemia, and hypoalbuminemia. These findings were compatible with hyper-interleukin (IL)-6 syndrome, namely, RA. It is known that hyper-IL-6 syndromes, such as multicentric Castleman's disease, RA, and other autoimmune diseases, fulfill the histological diagnostic criteria for IgG4-related disease. Therefore, hyper-IL-6 syndromes and IgG4-related disease cannot be differentially diagnosed by immunohistochemical staining alone. In conclusion, rheumatoid lymphadenopathy sometimes occurs with abundant IgG4(+) plasma cells, which is required for the differential diagnosis of IgG4-related disease.