D2-40 immunohistochemistry--so far!

Diagnostic Utility of Podoplanin Immunohistochemistry Combined with the NanoSuit-Correlative Light and Electron Microscopy Method for Thoracic Malignant Tumors

Background/Objectives: Differentiating thoracic malignant tumors, such as epithelioid malignant pleural mesothelioma (EMPM) and non-small-cell lung carcinoma (NSCLC), primarily comprising lung adenocarcinoma (LAC) and lung squamous cell carcinoma (LSCC), remains a challenge in routine pathological diagnosis. This study aimed to evaluate whether podoplanin (PDPN) immunohistochemistry combined with scanning electron microscopy (SEM) using the NanoSuit-correlative light and electron microscopy (CLEM) methods could serve as a reliable tool for distinguishing these thoracic malignancies. Methods/Results: Initially, PDPN expression was assessed by immunohistochemical analysis in 11 EMPM, 100 LAC, and 23 LSCC cases. PDPN positivity was predominantly observed in the cell membrane and was significantly more frequent in EMPM (100%) than in LAC (2%; p < 0.0001) or LSCC (43.5%; p = 0.0018). Subsequently, field emission-SEM (FE-SEM) observations of PDPN-positive sites on immunohistochemical slides, conducted using the NanoSuit-CLEM method, revealed distinctive ultrastructural features. EMPM exhibited densely packed, elongated microvilli, whereas such structures were absent in LAC and LSCC. Furthermore, analysis of thick-cut sections (20 μm) demonstrated extensive microvilli coverage characteristic of EMPM. Conclusions: These findings suggest that the combined approach of PDPN immunohistochemistry and FE-SEM observation of PDPN-positive sites, using the NanoSuit-CLEM method, constitutes an effective diagnostic strategy for enhancing the accuracy of distinguishing EMPM from NSCLCs.

Pulmonary lymphangiomatosis: insights into an ultra-rare disease

BACKGROUND

Pulmonary lymphangiomatosis (PL) is an ultrarare disease characterized by diffuse infiltration of the lung, pleura and/or mediastinum by abnormal lymphatic proliferation. Consented diagnostic or treatment approaches are not established. We therefore aimed to collect data on diagnostics and treatments in a cohort of patients with PL from a tertiary center for rare lung diseases.

METHODS

Clinical, radiological and outcome data from PL patients were collected retrospectively.

RESULTS

12 patients were diagnosed between 1996 and 2022 in our center. PL was diagnosed more commonly in female (58%), never smokers (75%) and younger patients (mean age 42 years). Main clinical symptoms comprised haem- and chyloptysis (58%) and dyspnea on exertion (83%). Pulmonary function was mostly restrictive (mean VC 59%) with impaired DLCO (mean 65%). Radiological assessment mainly showed mediastinal involvement (83%), and pleural effusion (67%), pleural thickening (67%) and bronchial wall thickening (67%) while interstitial changes were rare. Diagnosis was confirmed by surgical or transbronchial cryobiopsy. 8 patients were treated with sirolimus, 3 of these combined with a surgical intervention and in one case surgical intervention was necessary 9 months after initiation of sirolimus. Clinical and radiological improvement was demonstrated for all patients treated with sirolimus. 1 patient received a lung transplant due disease progression. Survival rates were 90% after a mean follow up of at least 3 months.

CONCLUSION

This case series illustrates the variability of the clinical presentation of PL. Among our patients, those treated with sirolimus showed significant clinical, functional and radiological improvement. However, further investigation is needed to understand the pathogenesis of lymphangiomatosis in order to establish therapeutic approaches.

Epithelioid inflammatory myofibroblastic sarcoma treated with Alectinib: a case report and literature review

Epithelioid inflammatory myofibroblastic sarcoma (EIMS) is an extremely rare and aggressive form of inflammatory myofibroblastic tumor. Clinically, it has a high risk of relapse and peripheral organ infiltration, and it responds poorly to conventional chemotherapy. Anaplastic lymphoma kinase (ALK) inhibitors are currently the most effective targeted therapy for EIMS. This report discusses a typical case of abdominal EIMS in a 43-year-old woman. The tumors recurred rapidly within one month after surgery. Alectinib was promptly administered upon diagnosis. However, the patient developed a severe allergic reaction to the medication. After a comprehensive assessment and symptomatic treatment, her condition stabilized, leading to a favorable prognosis. This study summarizes cases of abdominal EIMS, highlights the successful use of Alectinib for treatment, and discusses the management of medication-related complications.

A novel classification of senile dermatochalasis: insights from clinical and histological analysis

PURPOSE

Dermatochalasis is a common disorder of the elderly, often requiring upper blepharoplasty. Although it is mainly accepted as a process of aging, its clinical and histological findings vary among patients. The aim of this study was to classify types of dermatochalasis based on their clinical and histological findings.

METHODS

This retrospective study included patients with dermatochalasis who had undergone senile blepharoplasty at a single center. Clinical parameters such as margin-to-reflex distance 1 (MRD1), eyelid contour, visual field, and pre-existing medical conditions were assessed. Histological analysis was conducted of eyelid tissues stained with hematoxylin and eosin (H&E) and D2-40 to evaluate dermal edema, inflammation, lymphatic changes, and stromal depth.

RESULTS

This study included 67 eyes of 35 patients. The mean age of the patients was 69.0 ± 8.3 years, and the average MRD1 was 1.8 ± 1.3 mm. In correlation analysis, two distinct types of dermatochalasis based on the histological findings were identified: lymphangiectasia-dominant and stromal edema-dominant types. The difference between nasal and temporal side MRD1(NT-MRD1) showed the area under the ROC curve of 0.718 of for distinguishing the two histological types of dermatochalasis was 0.718.

CONCLUSION

Our novel classification of senile dermatochalasis based on morphological and histological analysis provides insights into the underlying pathology and may help to predict surgical outcomes and complications.

Primary germ cell tumours of the mediastinum: A review with emphasis on diagnostic challenges

This article will review current aspects of the histopathological, immunohistochemical and molecular analysis of primary mediastinal germ cell tumours (PMGCTs) as well as their aetiological, epidemiological, clinical and therapeutic features. PMGCTs represent an important differential diagnosis in the spectrum of mediastinal tumours, and their diagnosis is usually made on small tissue samples from core needle biopsies in combination with diagnostic imaging and serum tumour markers. As in lymphomas, a small biopsy is often the only viable tumour sample available from these patients, as they receive chemotherapy prior to eventual surgical resection. Pathologists therefore need to apply an efficient combination of immunohistochemical markers to confirm the diagnosis of a PMGCT and to exclude morphological mimics.

Fibroblasts Derived From Vestibular Schwannoma Express Protumorogenic Markers

BACKGROUND AND AIM

Vestibular schwannomas (VSs), despite being histologically benign, cause significant morbidity because of their challenging intracranial location and the propensity for growth. The role of the stroma and particularly fibroblasts, in the progression of VS, is not completely understood. This study examines the profile of fibroblasts in VS.

METHODS

Seventeen patients undergoing surgical excision of VS were recruited into the study. Reverse transcription with quantitative polymerase chain reaction (RT-qPCR) was performed on VS tissue samples and fibroblast-associated molecules examined. Immunofluorescence and immunohistochemistry in VS tissue were used to study the expression of fibroblast markers CD90 and podoplanin in situ. Fibroblast cultures were established from VS, and RT-qPCR analysis was performed on a panel of fibroblast markers on VS and control tissue fibroblasts.

RESULTS

Several fibroblast-associated molecules including members of galectin family and matrix metalloproteinases were found to be expressed in VS tissue on RT-qPCR analysis. In situ, expression of CD90 and podoplanin was observed in VS tissue both on immunohistochemistry and immunofluorescence. RT-qPCR analysis of fibroblasts from VS and control vestibular neuroepithelium (NE) showed a higher expression of several molecules of the galectin and matrix metalloproteinases family on VS fibroblasts compared with NE fibroblasts.

CONCLUSION

This work examines fibroblasts from VS and shows qualitative differences from NE fibroblasts on RT-qPCR. Further understanding of the fibroblast function in the progression of VS will potentially unveil new targets to manage VS growth.

Hepatic epithelioid hemangioendothelioma-a single-institution experience with 51 cases

Objectives

The aim of the present study was to describe the experience at a single institution in the management of hepatic epithelioid hemangioendothelioma (HEHE).

Methods

We included 51 patients with histologically confirmed HEHE. We performed log-rank (Cox-Mantel) survival analyses using Kaplan-Meier methods to test differences in survival between patients in different groups. Univariate Cox regression analyses and multivariate proportional hazards regression model were carried out to identify independent prognostic factors.

Results

Different imaging modalities were used to diagnose HEHE with various presentations. Liver resection (LR), liver transplantation (LT), systemic treatment (ST), and surveillance had been used in our study. A significant difference was noted between the LR group and the surveillance group with respect to mean survival (p = 0.006), as was in the LR group and the ST group (p = 0.036), and in surgical approach (LR and LT) and nonsurgical approach (ST and surveillance) (p = 0.008). The mean survival between the ST group and the surveillance group was not significantly different (p = 0.851). LR (p = 0.010) and surgical approach (p = 0.014) were favorable predictors of outcome, while macrovascular invasion (MaVI) (p = 0.037), lung metastasis (p = 0.040), and surveillance (p = 0.033) were poor prognostic factors in univariate analysis. Multivariate analysis showed that LR (p = 0.010) and surgical approach (p = 0.014) were independently associated with good OS, while surveillance (p = 0.033) was independently associated with poor OS. After adjusting for confounding factors, patients in the LR group have much better OS than those in the surveillance group (p = 0.013). However, there was no significant difference in OS between the LR group and ST group (p = 0.254), as was in the ST group and the surveillance group (p = 0.857).

Conclusions

The definitive diagnosis of HEHE was dependent on histopathology, and it was not possible to make a specific diagnosis without biopsy because the radiological findings were similar to those in some hepatic malignancies. ST was not recommended for patients who were not candidates for surgical approaches, and surgical approaches should be warranted regardless of disease stage. The retrospective nature and the small size of the data limited the generalizability of the study, designing a worldwide database that contains all data about patients with HEHE independent of their therapy, which was highly recommended.

Expression of Claudin-4 and D2-40 and their significance in prostatic adenocarcinoma

BACKGROUND

Claudins are a clan of proteins that are the most important component of tight junctions. The claudin-4 expression has been linked to tumour cell invasion and progression in a variety of primary malignancies. Evaluation of lymphovascular density (LVD) correlates with tumour aggressiveness and may correlate with prognosis. D2-40 is a highly specific marker of lymphatic vessels.

AIMS

To evaluate the claudin-4 expression in relation to LVD by D2-40 expression and with clinicopathological parameters in prostatic adenocarcinoma.

SETTINGS AND DESIGN

Prospective study.

MATERIALS AND METHODS

39 cases of prostatic adenocarcinoma were taken, the D2-40 and claudin-4 immunohistochemical stains were performed and correlation was done with clinicopathological parameters.

STATISTICAL ANALYSIS USED

Statistical analyses such as mean, median, standard deviation, Mann-Whitney U test, Fischer exact test, Spearman's rank-order correlation coefficient, Chi-square test and T-test were used.

RESULTS

The claudin-4 expression was seen higher in cases with higher Gleason score but it was statistically non-significant (P = 0.778). The claudin-4 expression did not correlate with any clinicopathological parameters. LVD in the peritumoral area was significantly higher as compared to the intratumoral area (P = 0.005). Intratumoral LVD and perineural invasion were found to be statistically significant (P = 0.048).

CONCLUSION

The claudin-4 expression may correlate with adverse prognostic parameters. Higher lymphatic vessels can be responsible for the higher metastatic potential of prostatic adenocarcinomas.

Kaposiform Lymphangiomatosis: Pathologic Aspects in 43 Patients

Kaposiform lymphangiomatosis is an uncommon generalized lymphatic anomaly with distinctive clinical, radiologic, histopathologic, and molecular findings. Herein, we document the pathology in 43 patients evaluated by the Boston Children's Hospital Vascular Anomalies Center from 1999 to 2020. The most frequent presentations were respiratory difficulty, hemostatic abnormalities, and a soft tissue mass. Imaging commonly revealed involvement of some combination of mediastinal, pulmonary, pleural, and pericardial compartments and most often included spleen and skeleton. Histopathology was characterized by dilated, redundant, and abnormally configured lymphatic channels typically accompanied by dispersed clusters of variably canalized, and often hemosiderotic, spindled lymphatic endothelial cells that were immunopositive for D2-40, PROX1, and CD31. An activating lesional NRAS variant was documented in 9 of 10 patients. The clinical course was typically aggressive, marked by hemorrhage, thrombocytopenia, diminished fibrinogen levels, and a mortality rate of 21%.

Roles of Podoplanin in Malignant Progression of Tumor

Podoplanin (PDPN) is a cell-surface mucin-like glycoprotein that plays a critical role in tumor development and normal development of the lung, kidney, and lymphatic vascular systems. PDPN is overexpressed in several tumors and is involved in their malignancy. PDPN induces platelet aggregation through binding to platelet receptor C-type lectin-like receptor 2. Furthermore, PDPN modulates signal transductions that regulate cell proliferation, differentiation, migration, invasion, epithelial-to-mesenchymal transition, and stemness, all of which are crucial for the malignant progression of tumor. In the tumor microenvironment (TME), PDPN expression is upregulated in the tumor stroma, including cancer-associated fibroblasts (CAFs) and immune cells. CAFs play significant roles in the extracellular matrix remodeling and the development of immunosuppressive TME. Additionally, PDPN functions as a co-inhibitory molecule on T cells, indicating its involvement with immune evasion. In this review, we describe the mechanistic basis and diverse roles of PDPN in the malignant progression of tumors and discuss the possibility of the clinical application of PDPN-targeted cancer therapy, including cancer-specific monoclonal antibodies, and chimeric antigen receptor T technologies.

Primary mediastinal germ cell tumours: an immunohistochemical and molecular diagnostic approach

AIMS

Primary mediastinal germ cell tumours (PMGCTs) are rare mediastinal neoplasms and their diagnosis can be challenging due to small biopsy samples. The aim of this study was to elaborate a diagnostic algorithm using immunohistochemical stainings with focus on novel markers and molecular analysis of isochromosome 12p [i(12p)].

METHODS AND RESULTS

Paraffin-embedded tissues of 32 mediastinal tumours were analysed using immunohistochemical stainings for SALL4, LIN28, OCT3/4, D2-40, CD117, SOX17, SOX2, CD30, ß-hCG, GATA3, FOXA2, GPC3, AFP, TdT, NUT and pan-cytokeratin. Quantitative real-time polymerase chain reaction (qPCR) was performed to investigate i(12p) status. Fifteen seminomas, seven teratomas, one yolk sac tumour, one choriocarcinoma and seven mixed PMGCT were diagnosed. Each entity had different immunohistochemical staining patterns which helped to distinguish them: seminoma (OCT3/4, D2-40, CD117, TdT), embryonal carcinoma (OCT3/4, SOX2), yolk sac tumour (FOXA2, GPC3, AFP) and choriocarcinoma (ß-hCG, GATA3). Mature teratomas stained positive for pan-cytokeratin in epithelial components and focally for SALL4, SOX2, GATA3, D2-40 and FOXA2. Furthermore, a NUT carcinoma mimicking a PMGCT was diagnosed showing a strong nuclear SOX2 and speckled nuclear NUT staining. i(12p) was detected in 24 out of 27 PMGCTs [89%].

CONCLUSION

A diagnostic algorithm is of great importance for a reliable diagnosis of PMGCTs in the usually small tissue biopsy samples. Therefore, a combination of three to four antibodies to identify the correct histological subtype is usually necessary in addition to morphological features. The i(12p) status serves as an additional option to underline germ cell origin in selected cases.

Haemolymphangioma of the small bowel mesentery in adults: two case reports and a literature review

BACKGROUND

Haemolymphangioma arising from the small bowel and its mesentery is extremely rare in the clinical setting. To date, only 8 cases of small bowel haemolymphangioma have been reported, and there have been no previously reported cases of haemolymphangioma in the small bowel mesentery (PubMed). The formation of this tumour is mostly congenital, but the exact mechanism is still unclear. As a benign tumour, the presentation of the disease may vary from a simple well-defined cystic lesion to an aggressive ill-defined lesion mimicking malignancy. However, there are no typical symptoms, and preoperative diagnosis is difficult.

CASE PRESENTATION

We present two cases of haemolymphangioma in the small bowel mesentery in a 54-year-old man and a 52-year-old woman. Both of them came to the hospital due to an abdominal mass. In the first case, a cystic teratoma in the left abdominal area was considered after abdominal plain computed tomography (CT) and magnetic resonance imaging (MRI) scans. After taking an enhanced CT scan, a lipoma was considered based on the images. In the second case, cystic masses of the left upper and middle abdomen were observed on abdominal ultrasonography. An abdominal plain CT scan showed an irregular low-density mass in the left upper and middle abdomen. With an enhanced CT scan, haemolymphangioma was considered based on the images. After complete surgical removal, the masses were found to originate from the small bowel mesentery and had not invaded into the peripheral lymphatic tissue. In case 1 in this study, the routine pathology diagnosis was lymphangioma, while in case 2, the diagnosis was haemangioma. The final diagnosis was confirmed to be haemolymphangioma by immunohistochemistry in both cases. No recurrence was evident during 4 months of follow-up. We review the previous case reports of haemolymphangioma in the abdominal cavity and discuss their clinical features, diagnosis, treatment and prognosis.

CONCLUSIONS

The clinical manifestations of abdominal haemolymphangiomas can vary for both location and size. Abdominal CT examination has important clinical value for haemolymphangioma in the abdominal cavity. The final diagnosis of haemolymphangioma depends on a postoperative pathological examination. In addition, postoperative regular follow-up is necessary.

Expression of Calretinin, Marker of Mesothelial Differentiation, in Pancreatic Ductal Adenocarcinoma: A Potential Diagnostic Pitfall

OBJECTIVE

Pancreatic ductal adenocarcinoma is one of the most common causes of "peritoneal carcinomatosis" and has an insidious growth pattern. Thus, it falls into the differential diagnosis of other peritoneal malignancies including malignant mesothelioma. Recently, we have encountered an undifferentiated pancreatic carcinoma presenting with peritoneal disease and exhibiting immunoreactivity to calretinin, mimicking mesothelioma. In this study, we explored the incidence of calretinin expression in pancreatic ductal adenocarcinoma.

MATERIALS AND METHODS

Calretinin immunohistochemical staining was performed on the tissue microarrays (TMAs), which were created using three 0.6 mm diameter punches per tumor (n=113). Distribution and intensity of expression were evaluated.

RESULTS

The TMAs contained 86 well/moderately differentiated and 27 poorly differentiated/undifferentiated carcinomas. Calretinin was positive in nine tumors (8%); six with diffuse and strong staining, three with focal and/or weak staining. The incidence of calretinin expression was 15% in poorly differentiated/undifferentiated carcinomas (vs. 6% in well/moderately differentiated carcinomas, p=0.03).

CONCLUSIONS

Pancreatic ductal adenocarcinomas, especially when poorly differentiated/undifferentiated, may be diffusely and strongly positive for calretinin creating a potential diagnostic challenge with malignant mesothelioma. Therefore, caution should be exercised when using this marker to explore a diagnosis of malignant mesothelioma. Tumors expressing calretinin without other mesothelial markers should prompt a careful evaluation of the morphologic and immunohistochemical features to exclude other malignancies. If the diagnosis of pancreatic ductal adenocarcinoma is considered, ductal differentiation can be demonstrated by using additional immunohistochemical markers such as mucin-related glycoproteins (MUC1, MUC5AC) and/or oncoproteins (CEA, B72.3, CA125).

Lymph Vessel Proliferation on Cardiac Biopsy May Help in the Diagnosis of Cardiac Sarcoidosis

Background The diagnosis of cardiac sarcoidosis ( CS ) is challenging because endomyocardial biopsy has only a 20% to 30% sensitivity rate for diagnosis and it presents with similar clinical features of idiopathic dilated cardiomyopathy ( DCM ). Lymphatic vessel proliferation in pulmonary sarcoidosis has been previously demonstrated. In this study, we compared endomyocardial biopsy samples obtained from patients with CS and DCM to determine whether lymph vessel counts using D2-40 immunostaining can be utilized as a complementary tool to distinguish CS from DCM . Methods and Results Endomyocardial biopsy tissues were obtained from 62 patients with CS (30 patients with a diagnosis made histologically, 32 patients with a diagnosis made clinically), and hematoxylin/eosin, Masson trichrome, and D2-40 immunostaining were performed. Their results were compared with those from 53 patients with DCM. The histological CS group showed significantly increased lymphatic vessels (12.0 [4.0-40.0] versus 2.6 [1.9-3.4], P<0.0001) and more severe mosaic fibrosis ( P<0.0001) compared with the DCM group. The optimal threshold was 7.5 lymphatic vessels, and this resulted in a sensitivity of 0.67 and specificity of 0.96. The clinical CS group diagnosed according to Japanese Circulation Society 2016 criteria showed increased lymphatic vessels (4.0 [3.3-9.0] versus 2.6 [1.9-3.4], P<0.0001), more severe mosaic fibrosis ( P<0.0001), more inflammatory cell infiltration (53% versus 0%, P<0.0001), and fatty infiltration within fibroblasts (50% versus 17%, P=0.0012) compared with the DCM group. The optimal threshold of lymphatic vessels was 3.5, which resulted in a sensitivity of 0.75 and specificity of 0.68. Conclusions Lymphatic vessel counts using D2-40 immunostaining may help to distinguish clinical CS without granuloma from DCM .

Vulvar lymphangiectasia secondary to gastrointestinal tuberculosis infection in a teenager

We report a rare presentation of vulvar lymphangiectasia that developed secondary to gastrointestinal tuberculosis in a teenager, and its spontaneous resolution after anti-tuberculous treatment was completed.

Podoplanin, a Potential Therapeutic Target for Nasopharyngeal Carcinoma

Introduction

The role of podoplanin (PDPN) in nasopharyngeal carcinoma (NPC) is still unknown. The aims of this study were to investigate the expression and role of PDPN in NPC cells.

Materials and Methods

Immunofluorescence staining and functional tests were used to determine the effects of PDPN knockdown by siRNA in TW01 NPC cells. Microarray analysis was conducted to identify genes regulated by PDPN. The molecular mechanism of PDPN on NPC cells was further determined by Ingenuity Pathways Analysis (IPA).

Results

PDPN was expressed in most TW01 NPC cells. PDPN knockdown by siRNA decreased NPC cell proliferation, migration, and invasion. The microarray data showed 63 upregulated genes and 12 downregulated genes following PDPN knockdown. The top 5 most upregulated genes analyzed by IPA were IFI27, IFI44L, IFI6, OAS1, and TRIM22, and the most relevant pathway was the interferon signaling pathway.

Conclusions

To the best of our knowledge, this is the first report to show that knocking down PDPN leads to suppression of NPC cell proliferation, migration, and invasion. Our results suggest that PDPN may serve as a potential chemotherapeutic target for NPC treatment in the future.

Pilar Cyst Pigmented Epithelial Remnants: A Potential Diagnostic Pitfall

Pilar cysts are common cutaneous cysts of follicular origin. They are easy to diagnose clinically and pathologically. Histologic diagnostic difficulties might arise in certain situations, however. Acute inflammation with total destruction of the cyst wall due to rupture with replacement by an abscess formation, foreign body giant cell reaction, and fibrosis could obscure their recognition. Cysts with hybrid lining epithelium could be confused with other cutaneous cysts. Epithelial remnants of the basal layer with loss of the squamous epithelium and shelled out cyst contents might mimic other epithelial cysts and vascular lesions. Few studies focused on the phenomenon of epithelial remnants or epithelial separation of pilar cysts. We report a case of a scalp cyst composed of a single layer of pigmented cuboidal lining epithelium. The initial differential diagnosis was hidrocystoma, solid-cystic hidradenoma, arteriovenous malformation, and lymphangioma. The intraepithelial pigment was melanin. The lining epithelium was positive for cytokeratin cocktail, CK5/6, CK8, CK19, p63, and D2-40 with scattered S-100 protein and melan-A positive melanocytes. Being unaware of the phenomenon of epithelial split in pilar cysts, it was mislabeled as a melanin-pigmented eccrine hidrocystoma. Surgical pathologists should be aware of pilar cysts' epithelial remnants to avoid potential diagnostic pitfalls. An attention to certain histologic hints and knowledge of the immunoprofile of the basal layer should help pathologists avoid this pitfall.

Renal Lymphatics: Anatomy, Physiology, and Clinical Implications

Renal lymphatics are abundant in the cortex of the normal kidney but have been largely neglected in discussions around renal diseases. They originate in the substance of the renal lobule as blind-ended initial capillaries, and can either follow the main arteries and veins toward the hilum, or penetrate the capsule to join capsular lymphatics. There are no valves present in interlobular lymphatics, which allows lymph formed in the cortex to exit the kidney in either direction. There are very few lymphatics present in the medulla. Lymph is formed from interstitial fluid in the cortex, and is largely composed of capillary filtrate, but also contains fluid reabsorbed from the tubules. The two main factors that contribute to renal lymph formation are interstitial fluid volume and intra-renal venous pressure. Renal lymphatic dysfunction, defined as a failure of renal lymphatics to adequately drain interstitial fluid, can occur by several mechanisms. Renal lymphatic inflow may be overwhelmed in the setting of raised venous pressure (e.g., cardiac failure) or increased capillary permeability (e.g., systemic inflammatory response syndrome). Similarly, renal lymphatic outflow, at the level of the terminal thoracic duct, may be impaired by raised central venous pressures. Renal lymphatic dysfunction, from any cause, results in renal interstitial edema. Beyond a certain point of edema, intra-renal collecting lymphatics may collapse, further impairing lymphatic drainage. Additionally, in an edematous, tense kidney, lymphatic vessels exiting the kidney via the capsule may become blocked at the exit point. The reciprocal negative influences between renal lymphatic dysfunction and renal interstitial edema are expected to decrease renal function due to pressure changes within the encapsulated kidney, and this mechanism may be important in several common renal conditions.

Pleural Epithelioid Hemangioendothelioma: A Case Report and Literature Review

Epithelioid hemangioendothelioma (EHE) is a rare neoplasm of vascular origin that can arise in multiple and varied tissue sites. Pleural epithelioid hemangioendothelioma (PEH), a subtype of EHE, is particularly less reported. Herein, we describe a case of PEH presented with left-sided back pain in a 68-year-old female, and her chest CT scan revealed thickening of the left pleura and left pleural effusion, the histological diagnosis was confirmed by both conventional examination and immunohistochemistry. A literature search utilizing PubMed, Embase, Ovid and Cochrane, Wanfang and Chinese National Knowledge infrastructure (CNKI) for PEH was conducted to investigate the characteristics of the disease, 26 related articles were retrieved and 40 cases of PEH were reported. According to available literature, the average age at presentation is 51.8 years and the disease occurred more often in men than women. The etiology of the disease remained unknown. Chest pain, cough, and dyspnea were the common symptoms. Computed tomography usually revealed pleural effusion and pleural thickening. Histological examinations revealed mainly epithelioid cells. Immunohistochemical stains were positive for vascular endothelial markers. PEH tends to have more aggressive behavior than tumors in other locations, thus effective treatment has not yet been established until now. Further studies are needed to analyze the prognostic factors, clinical features and treatment of PEH.

Lymphangioma on 68Ga-NOTA-Evans Blue PET/MRI

A 17-year-old adolescent boy with a history of hypoproteinemia underwent Ga-NEB PET/MRI to evaluate possible lymphatic disorders suggested by FDG PET/CT imaging. The images revealed multiple lesions with increased Ga-NEB uptake and high signal on T2-weighted images, consistent with likely lymphatic disorder. Histopathological examination from biopsied specimen confirmed lymphangioma.

Preparation of Anti-Human Podoplanin Monoclonal Antibody and its application in Immunohistochemical Diagnosis

Podoplanin (PDPN), a 38 kDa transmembrane sialoglycoprotein from human, is expressed in lymphatic endothelial cells but not in vascular endothelial cells, and has been considered as a specific marker of lymph. In this study, the gene encoding the extracellular part of PDPN (ePDPN) was synthesized and used to expressed fusion protein ePDPN-His and GST-ePDPN, respectively, in E.coli. The purified GST-ePDPN fusion protein was mixed with QuickAntibody-Mouse5W adjuvant to immune mice, and the antiserum titer was determined by indirect ELISA. A stable cell line named 5B3 generating anti-PDPN monoclonal antibody (mAb) was obtained by hybridoma technology. The isotype of 5B3 cell line was IgG_2b, and the chromosome number was 102 ± 4. The 5B3 mAb was purified successfully from ascites fluid through Protein G column, and its affinity constant was 2.94 × 10⁸ L/mol. Besides, excellent specificity of the 5B3 mAb was further demonstrated in ELISA, western blot and immunohistochemistry experiments, suggesting that 5B3 mAb displays similar application value to D2-40, a commercial available antibody. Hence, the current study provides conclusive guidelines for preparation of other mAbs and their applications in immunohistochemistry diagnosis.

Cytologic features, immunocytochemical findings, and DNA ploidy in four rare cases of epithelioid hemangioendothelioma involving effusions

BACKGROUND

Epithelioid hemangioendothelioma (EHE) involving serous effusion is extremely rare, and the diagnosis can be challenging. DNA ploidy quantitation of EHE in effusion fluids has not been previously described in the English-language literature.

METHODS

Specimens of cytological diagnosed with EHE in effusion fluids between 2002 and 2009 were retrieved from the pathology files at MD Anderson Cancer Center. A total of four cases of EHE involving or arising from effusion fluids were found, and we reviewed cytospin, smears, cell block sections, and immunostained slides. DNA image analysis for ploidy and proliferation evaluation was performed on a destained, papanicolaou-stained slide from each case.

RESULTS

The tumor cells were epithelioid with prominent cytoplasmic vacuolization and intracytoplasmic inclusions, which could resemble reactive mesothelial cells, mesothelioma, or adenocarcinoma. The tumor cells were positive for endothelial markers. DNA image analysis in three of the four cases revealed predominantly diploid and tetraploid subpopulations, with few aneuploid cells and fairly low proliferation indices, and these patients had fairly prolonged survival.

CONCLUSIONS

DNA image analysis is useful for differentiating EHE from reactive mesothelial cells and high-grade carcinoma. For accurate diagnosis of EHE in effusion fluids, cytologic features should be considered together with clinical history and ancillary studies.

Rare Case of Pancreatic Cystic Lymphangioma

Pancreatic cystic lymphangioma is an extremely rare tumor. The characteristic imaging findings are poorly defined, and distinguishing between this disease and other pancreatic cyst-related tumors is very difficult. We herein report a case of a Japanese woman in her 50s with this lesion, located in the tail of the pancreas. Pancreatic cystic lymphangioma should therefore be considered in the differential diagnosis of pancreatic cystic lesions. Laparoscopic resection can be a useful, minimally invasive surgical approach for treating these cysts as well as for the treatment of benign or low-grade malignant tumors located in the pancreatic body or tail.

Update from the 4th Edition of the World Health Organization of Head and Neck Tumours: Tumours of the Oral Cavity and Mobile Tongue

There have been several additions and deletions in Chapter 4 on Tumours of the oral cavity and mobile tongue in the 2017 fourth edition of the World Health Organization Classification of Tumours of the Head and Neck. This chapter excludes the oropharynx, which now is a stand-alone chapter acknowledging the uniqueness of the oropharynx from the oral cavity. New entries in Chapter 4 include rhabdomyoma, haemangioma, schwannoma, neurofibroma and myofibroblastic sarcoma in the section titled Soft tissue and neural tumours. Discussion of salivary gland entities have been reduced and includes mucoepidermoid carcinoma and pleomorphic adenoma as the other salivary gland types are discussed elsewhere. In the Haematolymphoid tumours section, like the salivary gland section, only tumors that commonly present in the oral cavity are discussed in Chapter 4. Excluded entities in the updated classification include papillary hyperplasia, median rhomboid glossitis, keratoacanthoma, focal oral mucinosis, and secondary tumors. This article will summarize the changes in the new classification since the 2005 edition focusing on selected entities that have had significant changes along with new entries.

Benign vascular lesions of the lips: Diagnostic approach

BACKGROUND

Although not rare, vascular lesions occurring in the lips sometimes poses a difficult in properly diagnosing and handling them. In this study, vascular lesions occurring in the lips were retrieved from an Oral Pathology Service.

METHODS

Among 5600 biopsies, 131 cases were found. The following diagnoses were attributed: caliber-persistent artery, infantile hemangioma, vascular malformation, venous lake, thrombus, papillary endothelial hyperplasia and pyogenic granuloma. Clinical data were obtained from patients' records.

RESULTS

The lesions' frequency were: pyogenic granuloma (48%), followed by venous lake (17.5%), thrombus (14.5%), papillary endothelial hyperplasia (9.1%), infantile hemangioma (6.1%), caliber-persistent artery (3%) and vascular malformation (1.5%). Glucose transporter protein of the erythrocyte type was positive only in infantile hemangioma. The other markers (CD34 and smooth muscle action) were positive in all lesions, except for podoplanin, which was negative.

CONCLUSION

It is important to be aware of the occurrence of different vascular lip lesions and their histomorphologies in order to properly handle them. Despite most lesions do not represent any risk to the patient, some of them can reach large dimensions and thus cause aesthetical trouble. Immunohistochemistry may help when the vascular character of the lesion is not promptly determined and to differentiate among some lesions.

Vasculogenic mimicry in malignant mesothelioma: an experimental and immunohistochemical analysis

Vasculogenic mimicry, the process in which cancer cells form angiomatoid structures independent of or in addition to host angiogenesis has been recorded in several otherwise non-endothelial malignant neoplasms. This study describes evidence of routine vascular mimicry by human mesothelioma cell lines in vitro, when the cell lines are cultured alone or co-cultured with human umbilical vascular endothelial cells, with the formation of angiomatoid tubular networks. Vasculogenic mimicry is also supported by immunohistochemical demonstration of human-specific anti-mitochondria antibody labelling of tumour-associated vasculature of human mesothelioma cells xenotransplanted into nude mice, and by evidence of vascular mimicry in some biopsy samples of human malignant mesotheliomas. These studies show mosaic interlacing of cells that co-label or label individually for immunohistochemical markers of endothelial and mesothelial differentiation. If vascular mimicry in mesothelioma can be characterised more fully, this may facilitate identification of more specific and targeted therapeutic approaches such as anti-angiogenesis in combination with chemotherapy and immunotherapy or other therapeutic approaches.

Lymphatics in Neurological Disorders: A Neuro-Lympho-Vascular Component of Multiple Sclerosis and Alzheimer's Disease?

Lymphatic vasculature drains interstitial fluids, which contain the tissue's waste products, and ensures immune surveillance of the tissues, allowing immune cell recirculation. Until recently, the CNS was considered to be devoid of a conventional lymphatic vasculature. The recent discovery in the meninges of a lymphatic network that drains the CNS calls into question classic models for the drainage of macromolecules and immune cells from the CNS. In the context of neurological disorders, the presence of a lymphatic system draining the CNS potentially offers a new player and a new avenue for therapy. In this review, we will attempt to integrate the known primary functions of the tissue lymphatic vasculature that exists in peripheral organs with the proposed function of meningeal lymphatic vessels in neurological disorders, specifically multiple sclerosis and Alzheimer's disease. We propose that these (and potentially other) neurological afflictions can be viewed as diseases with a neuro-lympho-vascular component and should be therapeutically targeted as such.

Pseudoangiomatous Stromal Hyperplasia in Core Needle Biopsies of Breast Specimens

BACKGROUND

Pseudoangiomatous stromal hyperplasia (PASH) is a benign lesion of myofibroblasts that is composed of a network of slit-like channels that resemble vascular spaces. The aims of this study were to document the frequency of PASH in core needle biopsy specimens (CNBS) of the breast, to describe which histopathologic findings coexist with PASH and to examine any endothelial cell differentiation.

MATERIALS AND METHODS

We reevaluated hematoxylin and eosin-stained sections of all CNBS that were obtained during a 1-year period. First, we performed CD34 and CD31 immunostainings to highlight the areas of PASH, then performed D2-40/podoplanin (lymphatic endothelial marker) and Fli-1 (vascular endothelial cell marker) immunostains.

RESULTS

The total number of CNBS was 412. Areas of PASH were noted in 37 of the 412 cases (9%), with a mean age of 38.5 years. The lesions that were described in association with PASH were "benign breast parenchyma with stromal fibrosis" (17/37; 46%), "fibroepithelial tumors" (17/37; 46%), "columnar cell changes (CCC)" (2/37; 5%), and "invasive carcinoma" (1/37; 3%). There were 2 cases of CCC within the foci of PASH (direct contact with PASH), and 8 additional cases of CCC that coexisted in the same specimen but were not in direct contact. There was no staining for D2-40 or Fli-1 within PASH foci.

CONCLUSION

PASH lesions occurred with a frequency of 9% in CNBS and were mostly in association with benign breast lesions in premenopausal women. CCC was determined as an accompanying epithelial lesion within or near PASH areas. No obvious immunopositivity compatible with endothelial cell differentiation was revealed.

Disorders of the lymphatic system of the abdomen

The lymphatic system of the abdomen comprises of the cisterna chyli, its major and minor lymphatic tributaries, and lymph nodes. Disorders of the lymphatic system of the abdomen are rarely encountered and consist of primary and secondary types. Abdominal lymphangiomas constitute the majority and have characteristic imaging features. Complicated lymphangiomas may pose a diagnostic dilemma. Generalised systemic lymphangiomatosis is a rare condition and affects major organs with a poor prognosis. Retroperitoneal lymphangiectasia in the appropriate setting might predict underlying infection, such as filariasis. Other acquired conditions include iatrogenic or treatment-induced chylocoele. Chylous ascites can be secondary to multiple causes and can be confirmed by biochemical testing and lymphangiogram in appropriate settings.

Classical Kaposi sarcoma: case reports with unusual presentation on the penis and scrotum

BACKGROUND

Kaposi sarcoma (KS) is the most common vascular neoplasm. Any skin area could be involved, including the genitalia. Traditionally, classic KS lesions have a general distribution, often involving skin of the feet and legs, and to a lesser extent, that of the hands, arms, and trunk. KS limited to the external genitalia is extremely rare in HIV seronegative individuals.

METHODS

We report six patients of classic KS with generalized dermal KS lesions.

RESULTS

Two of them presenting with unusual KS lesions on the penis and scrotum beside the other dermal lesions. Patients were HIV negative and human herpes virus eight positive. Histological examination showed classical KS.

CONCLUSIONS

Primary KS of the penis and scrotum is rare but could occur in HIV-negative patients.

Absence of Lymphatic Vessels in PCNSL May Contribute to Confinement of Tumor Cells to the Central Nervous System

Primary central nervous system (CNS) lymphoma (PCNSL) is a mature lymphoma of the diffuse large B-cell lymphoma (DLBCL) type confined to the CNS. Despite cytomorphological similarities between PCNSL and systemic DLBCL, molecular differences between both entities have been identified. The exclusively topographical restriction of PCNSL to the CNS is an unexplained mystery. To address the question of whether the unique lymphatic drainage system of the CNS, which differs from that of other organs, may play a role for this peculiar behavior, we investigated a series of 20 PCNSLs for the presence of lymphatic vessels by immunohistochemistry for Lyve-1, podoplanin, and Prox-1 expression. All PCNSLs lacked lymphatic vessels and, in this regard, were similar to 20 glioblastoma multiforme samples. In contrast to these tumors, all of which were located in the deep brain parenchyma, dural and meningeal DLBCL harbored lymphatic vessels that expressed Lyve-1 (3/8 tumors), podoplanin (5/8 tumors), and Prox-1 (5/8 tumors) in areas where the tumors had invaded the fibrous tissue of the dura. These data indicate that local topographical characteristics of the specific lymphatic drainage system may contribute to confinement of the tumor cells in PCNSL and malignant gliomas.

Hemolymphangioma of Greater Omentum: A Rare Case Report

Hemolymphangioma is a rare vascular developmental error. It comprises malformed venous and lymphatic component in various proportion. To the best of our knowledge, only a few cases have been reported in the literature so far. Here, we report a case of huge intraperitoneal cystic mass in a 3-year-old boy that was presented to hospital with intractable abdominal pain. On examination, he had fever along with associated symptoms like cough and sputum. Abdomen was distended with no tenderness or rebound tenderness. On computed tomography scan, huge cystic mass was seen and was diagnosed as intraperitoneal benign cystic lesion. Excisional surgery of the lesion was planned. On surgery, lesion was found to be originated from greater omentum and no adhesion was seen in surrounding tissue. Complete excision of the lesion was done. Histopathological specimen after surgery suggested it to be hemolymphangioma. Follow-up for 6 months showed no recurrence.Hemolymphangioma of the greater omentum is benign tumor and accurate diagnosis before surgery is still a challenge. Presentation of disease may vary from simple well-defined cystic lesion to aggressive ill-defined lesion mimicking malignancy. Therefore, further research is needed to help doctor with preoperative radiological diagnosis and avoid unnecessary radical surgery.

Diffuse, encasing lymphangioma of the supraglottis

BACKGROUND

Lymphangioma of the head and neck is considered a rare congenital tumor with the vast majority presenting before two years of age. Surgical excision and sclerosing therapy using OK-432 are recognized as effective treatment options for the majority of these lesions; however, treatment options of laryngeal lesions are less straightforward due to the risk of airway compromise and the desire to maintain the integrity of a functional larynx. We present the case of a four month old male who presented with chief complaint of inspiratory stridor after a single episode of pneumonia. His clinical presentation, flexible fiberoptic laryngoscopic examination, and operative evaluation were consistent with a lymphangioma completely encasing the epiglottis and arytenoids and isolated to the supraglottis. This report outlines our approach to workup and treatment of this rare lesion.

METHOD

Case report of presentation, diagnosis and treatment is presented.

RESULTS

A four-month old male presented to ENT clinic with inspiratory stridor, worsened with crying, without frank respiratory distress. History and initial examination was consistent with airway obstruction. Flexible fiberoptic laryngoscopy showed laryngomalacia as well as diffuse and symmetric supraglottic edema. Surgical evaluation identified edema limited to the supraglottis, notably along the ventral surface of the epiglottis and dorsal surface of bilateral arytenoids. Biopsies were taken and immunohistochemical staining was performed with strong positivity for D2-40 and CD31, supporting the diagnosis of isolated lymphangioma of the supraglottis. Treatment was performed through multiple point spot welding with a fiber equipped CO2 LASER (OmniGuide TM) at 5 watt continuous power.

CONCLUSION

Isolated supraglottic lymphangioma was diagnosed via direct laryngoscopy, with pathologic and immunohistochemical confirmation. Carbon dioxide laser spot welding technique was used with excellent clinical improvement in stridor. Clinical improvement is sustained after 6 months follow-up.

Dual use of E-cadherin and D2-40 immunostaining in unusual meningioma subtypes

OBJECTIVES

Meningiomas usually can be readily diagnosed on H&E alone, although occasionally immunohistochemistry (IHC) confirmation is desirable. Studies exploring the diagnostic utility of either podoplanin (D2-40) or E-cadherin IHC in meningiomas have conflicted, and no studies exist in which the two IHCs have been used in combination for diagnosis.

METHODS

E-cadherin and D2-40 IHC was performed on 77 meningiomas (31 ordinary; eight microcystic; four rare myxoid; six metaplastic; six invasive of orbit, muscle, and/or soft tissue; two metastatic; six brain-invasive World Health Organization [WHO] grade II, nine non-brain-invasive WHO grade II; and five anaplastic WHO grade III), with semi-quantitative scoring on a three-tier scale (0, focal [1+], strong/diffuse [2+]).

RESULTS

All meningiomas were either E-cadherin or D2-40 IHC+, with 69 of 77 showing dual immunostaining, most at the 2+ level. No downregulation of E-cadherin IHC was found in invasive or high-grade meningiomas.

CONCLUSIONS

Dual E-cadherin/D2-40 IHC can supplement diagnosis of meningioma.

Prognostic Significance of Lymphatic Vessel Density Detected by D2-40 and Its Relation to Claudin-4 Expression in Prostatic Adenocarcinoma

Background Lymphovascular invasion is an important pathway of metastatic spread and regional lymph node metastasis is the major prognostic factor in prostatic adenocarcinoma. D2-40 is used to identify the lymphatic vessels and to assess the lymphatic vessel density (LVD). Expression of claudin-4 may be related to invasion and progression of carcinoma cells in several primary tumors. Aim To evaluate intra- and peritumoral LVD through immunohistochemical expression of D2-40 in relation to claudin-4 expression and clinicopathological parameters in prostatic adenocarcinoma. Materials and Methods Immunohistochemical staining procedure was performed on 53 paraffin-embedded blocks of radical prostatectomy specimens for prostatic adenocarcinoma using anti D2-40 and claudin-4 antibodies. Sections were evaluated for mean LVD in intratumoral and peritumoral tissues assessed by D2-40 expression. Results LVD in intratumoral tissues was significantly lower compared with peritumoral areas (P = .0001). Peritumoral mean LVD was significantly higher in cases with lymphovascular invasion (P = .041) and in cases with positive lymph node metastasis (P = .003) than intratumoral mean LVD. High claudin-4 expression was significantly correlated with high tumor grade (P = .0001), lymphovascular invasion (P = .006), and positive lymph node metastasis (P = .004). High claudin-4 expression was significantly associated with increased mean LVD in peritumoral tissues. Conclusion Increased peritumoral mean LVD in prostatic adenocarcinoma is associated with lymphovascular invasion and positive lymph node metastasis. High claudin-4 expression is associated with high tumor grade, lymphocascular invasion, positive lymph node metastasis, and high mean peritumoral LVD suggesting that D2-40 and claudin-4 may represent different mechanisms of lymphatic vessel invasion with both biomarkers is related to poor prognosis.

The different role of intratumoral and peritumoral lymphangiogenesis in gastric cancer progression and prognosis

Background

Tumor-induced lymphangiogenesis plays a crucial role in metastasis and tumor progression. However, the significance of intratumoral lymphovascular density (I-LVD) and peritumoral lymphovascular density (P-LVD) has been controversial in gastric cancer. The purpose of this study was to investigate the differences of clinicopathologic characteristics with respect to I-LVD and P-LVD in gastric cancer.

Methods

Samples of I-LVD and P-LVD from 66 patients who had undergone radical gastrectomy for gastric cancer were assessed after staining with D2-40, an immunostaining marker for lymphatic endothelium. The mean number of lymphatic vessels in three hotspots was calculated in intratumoral and peritumoral areas.

Results

The peritumoral lymphatics were enlarged with dilated lumens compared to the intratumoral lymphatics. I-LVD was positively correlated with diffuse gastric cancer subtype, tumor stage, lymphovascular invasion, tumor node metastasis stage, and overall survival (P <0.05). P-LVD was associated with lymphovascular invasion, node stage, and disease-free survival (P <0.05).

Conclusions

We conclude that P-LVD had an important role in lymph node metastasis, while I-LVD was more associated with depth of tumor invasion. However, both LVDs contributed to gastric cancer progression and prognosis.

Epithelioid hemangioendothelioma: a study of 14 cytopathology cases

INTRODUCTION

The cytopathologic diagnosis of the rare vascular tumor epithelioid hemangioendothelioma (EHE) in patients who have no previous history of EHE or who have a complicated and/or misleading disease history is challenging. Furthermore, few studies have described the cytopathology of EHE. Herein, we identify 14 cases of EHE from 10 patients, some of whom had a history of epithelial tumor, and provide a detailed report of the cytomorphology of EHE, discuss the tumor's differential diagnoses, and describe ancillary examinations that may be helpful in diagnosing EHE cytologically, especially in patients with a complex disease history.

MATERIALS AND METHODS

We retrieved the slides of 14 cases of EHE archived between 2002 and 2009 in our institution's cytology section. Conventional direct smears and cell block sections were prepared from most fine-needle aspiration samples and from all effusion samples. Cell block sections were subjected to immunostaining for vascular, mesothelial, and epithelial markers.

RESULTS

EHE shared many morphologic features with other, more common tumors such as adenocarcinoma and mesothelioma. The defining cytologic feature of EHE was an intracellular lumen containing entrapped intact and degenerating erythrocytes, which was not present in every case. EHE cells were positive for the vascular markers CD34, CD31, factor VIII, and friend leukemia integration 1 transcription factor (FLI-1) and negative for epithelial and mesothelial markers. Clinicians provided information important to the diagnosis of EHE.

CONCLUSIONS

Carefully examining the smear and cell block sections for morphologic features indicative of EHE (eg, prominent cytoplasmic vacuolization, intranuclear cytoplasmic inclusions, and intracellular lumen containing entrapped intact and degenerating erythrocytes), confirming these findings with immunocytochemical staining, and communicating with clinicians are all important to correctly diagnosing EHE.

Lymphatic endothelial cancerization in papillary thyroid carcinoma: hidden evidence of lymphatic invasion

We hypothesize that cystic structures in metastatic papillary thyroid carcinoma (PTC) develop along the framework of lymphatic channels. To investigate this phenomenon, different categories of PTC were immunostained for D2-40 and TTF1. In this study, reactivity for D2-40 was considered as positive when there is membranous staining as often seen in lymphatic endothelial cells. Thirty cases of PTC with lymph node metastasis or with potential for lymphatic invasion and 20 cases metastatic PTC in lymph nodes were reviewed and found to show double/mosaic immunoreactivity for TTF1/D2-40 in 40-100% of cases. PTC metastasis in lymph nodes with cysts and some branching lymphatic-like channels lined by follicular cells with or without nuclear features of PTC were diffusely reactive to TTF1, and focally to D2-40. For primary and metastatic PTC, focal membranous D2-40 reactivity was also demonstrated in cysts or cleft linings. For25 thyroid neoplasms with no known potential for lymphatic invasion, there was no such immunoreactivity. The mosaic or double immunoreactivity for TTF1/D2-40 suggests lymphatic cancerization and possible endothelial mimicry of follicular cells. Mosaic/double immunoreactivity is helpful to detect the hidden pattern of lymphatic invasion masquerading as 'benign-appearing' follicles and supports our hypothesis of malignant cells developing along the lymphatic framework.

Adrenal Gland Lymphangiomas

Lymphangiomas of the adrenal glands (ALs) are benign vascular lesions. Approximately, 53 cases have been reported in the literature. The current study reviews and analyzes the clinical and pathologic features of all reported ALs and additionally illustrates a typical case of adrenal lymphangioma (AL). In order to perform the review analysis, a search of the international literature for ALs in adults was conducted. Thirty-eight related articles were found. Clinical and pathological information were obtained for all the reported cases and a database was created. ALs were detected more frequently in women than men. The mean age of occurrence was 39.5 years, while their mean size was 8.86 cm. Fifty-nine percent of ALs were right-sided. Size and localization were responsible for the presenting symptoms, though 30.4 % were asymptomatic. Diagnosis was made postoperatively in all cases by histological results. ALs are rare and benign lesions. They usually present as an incidental finding after abdominal imaging. The diagnosis is made after the surgical removal by histological and immunohistochemical examinations.

Histological and clinical findings in patients with post-transplantation and classical encapsulating peritoneal sclerosis: a European multicenter study

BACKGROUND

Encapsulating peritoneal sclerosis (EPS) commonly presents after peritoneal dialysis has been stopped, either post-transplantation (PT-EPS) or after switching to hemodialysis (classical EPS, cEPS). The aim of the present study was to investigate whether PT-EPS and cEPS differ in morphology and clinical course.

METHODS

In this European multicenter study we included fifty-six EPS patients, retrospectively paired-matched for peritoneal dialysis (PD) duration. Twenty-eight patients developed EPS after renal transplantation, whereas the other twenty-eight patients were classical EPS patients. Demographic data, PD details, and course of disease were documented. Peritoneal biopsies of all patients were investigated using histological criteria.

RESULTS

Eighteen patients from the Netherlands and thirty-eight patients from Germany were included. Time on PD was 78(64-95) in the PT-EPS and 72(50-89) months in the cEPS group (p>0.05). There were no significant differences between the morphological findings of cEPS and PT-EPS. Podoplanin positive cells were a prominent feature in both groups, but with a similar distribution of the podoplanin patterns. Time between cessation of PD to the clinical diagnosis of EPS was significantly shorter in the PT-EPS group as compared to cEPS (4(2-9) months versus 23(7-24) months, p<0.001). Peritonitis rate was significantly higher in cEPS.

CONCLUSIONS

In peritoneal biopsies PT-EPS and cEPS are not distinguishable by histomorphology and immunohistochemistry, which argues against different entities. The critical phase for PT-EPS is during the first year after transplantation and therefore earlier after PD cessation then in cEPS.

Podoplanin (D2-40) is a reliable marker of urinary bladder myofibroblasts (telocytes)

Podoplanin, D2-40, has been described in a variety of normal and neoplastic tissues. It is often used for highlighting lymphatics. We evaluated the expression of podoplanin in α-smooth muscle actinpositive myofibroblasts producing the suburothelial layer in tunica propria of the urinary bladder that have some similar features with telocytes. Our results showed that these cells demonstrate distinct D2-40 immunoreactivity from telocytes occurring in the renal pelvis and ureter. We observed positive reaction not only in bioptic specimens from women with interstitial cystitis, but also in a control group of women and men treated for pathological bladder lesion different from interstitial cystitis. It is interesting that identical staining reaction was observed in the ureters only exceptionally. In addition, we examined samples from myofibroblastic tumoriform lesions of soft tissue such as nodular fascitis and fibromatosis (desmoid) and we obtained negative results. It means that the so-called myofibroblasts of urinary bladder tunica propria have a unique immunophenotype that has probably not been described until now. Our findings suggest that D2-40 can be used as a complementary immunostainer to α-smooth muscle actin on urinary bladder biopsies from patients with interstitial cystitis. The role of D2-40 as an immunohistochemical marker is still being investigated.

ERG expression in epithelioid sarcoma: a diagnostic pitfall

ERG transcription factor is constitutively expressed in endothelial cells. Because benign and malignant vascular endothelia retain the ERG expression, ERG is considered a useful marker for angiosarcomas and related tumors. ERG is also expressed in a subset of prostate carcinomas and Ewing sarcomas due to ERG-involved translocations; therefore, this marker is also of high interest in the study of these malignancies. In this study, we evaluated 109 epithelioid sarcomas for ERG expression, on the basis of an initial observation of an ERG-positive case. We also studied expression of other endothelial antigens in epithelioid sarcoma. ERG was expressed in 38% of epithelioid sarcomas (41/109), usually with a uniform nuclear staining, similar to that seen in angiosarcomas. However, all epithelioid sarcomas were negative for ERG gene rearrangement indicating that ERG expression is not likely related to ERG-involving translocations in epithelioid sarcoma. Other endothelial markers, CD31, claudin 5, and Prox1, were absent in epithelioid sarcomas. The only exception was a pulmonary metastasis of epithelioid sarcoma showing focal CD31 expression, which probably resulted from antigen adsorption onto tumor cell surfaces. However, podoplanin was commonly (7/9) expressed in epithelioid sarcoma; therefore, this marker is not useful in distinguishing epithelioid sarcoma from angiosarcoma. INI1/SMARCB1 gene product was absent in all epithelioid sarcomas (considered here a definitional feature) but was absent from only 1 epithelioid angiosarcoma, indicating its relative specificity for epithelioid sarcoma in this differential diagnostic setting. ERG expression is fairly common in epithelioid sarcoma and should be recognized as a diagnostic pitfall in the differential diagnosis of epithelioid sarcoma and epithelioid angiosarcoma. General lack of endothelial cell-specific markers in epithelioid sarcoma helps in this distinction.