Differentiation of vascular tumors from vascular malformations by expression of Wilms tumor 1 gene: evaluation of 126 cases

Soft tissue sarcoma mimicking an arteriovenous malformation - A case report and review of literature

INTRODUCTION AND IMPORTANCE

Arteriovenous malformation (AVM) is a rare condition affecting less than 5/10,000 people, with high misdiagnosis due to its heterogeneity, inconsistent nomenclature, and diverse diagnostic criteria. Understanding its prevalence in this age group is crucial for effective treatment. Here we present a case report of a patient with AVM. IRB approval and patient consent were obtained. This study was done based on SCARE criteria.

CASE PRESENTATION

A 53-year-old female patient was diagnosed with a right hip vascular mass suggestive of AVM. The patient reported painless swelling on the right hip for five years, initially increasing in size but significantly increasing in the last six months. The patient had no history of trauma, neurological or pelvic symptoms, or constitutional symptoms. An examination of the lower limbs revealed a firm, non-tender mass measuring approximately 15 × 15 cm. A thigh MRI revealed a sizable, well-rounded, lobulated soft tissue mass with a stromal structure and pronounced vascularity, indicative of a soft tissue tumor.

CLINICAL DISCUSSION

AVMs misdiagnosis is a significant issue, with 40 % of soft tissue sarcomas still misdiagnosed delaying care and leading to unnecessary measures. A 2015 study found 42.5 % of AMV patients were misdiagnosed, and 71 % were misdiagnosed as hemangiomas. Management involves multidisciplinary approaches, including radiology, sclerotherapy, surgical resection, and chemo/radiotherapy. Sirolimus may improve AVM prognosis.

CONCLUSION

Misdiagnosis of AVMs is a significant issue, with 40 % of soft tissue sarcomas still misdiagnosed. Management involves multidisciplinary approaches, including interventional radiology, sclerotherapy, surgical resection, and chemo/radiotherapy.

Wilms' tumor 1 (WT1) antigen is overexpressed in Kaposi Sarcoma and is regulated by KSHV vFLIP

In people living with HIV, Kaposi Sarcoma (KS), a vascular neoplasm caused by KS herpesvirus (KSHV/HHV-8), remains one of the most common malignancies worldwide. Individuals living with HIV, receiving otherwise effective antiretroviral therapy, may present with extensive disease requiring chemotherapy. Hence, new therapeutic approaches are needed. The Wilms' tumor 1 (WT1) protein is overexpressed and associated with poor prognosis in several hematologic and solid malignancies and has shown promise as an immunotherapeutic target. We found that WT1 was overexpressed in >90% of a total 333 KS biopsies, as determined by immunohistochemistry and image analysis. Our largest cohort from ACTG, consisting of 294 cases was further analyzed demonstrating higher WT1 expression was associated with more advanced histopathologic subtypes. There was a positive correlation between the proportion of infected cells within KS tissues, assessed by expression of the KSHV-encoded latency-associated nuclear antigen (LANA), and WT1 positivity. Areas with high WT1 expression showed sparse T-cell infiltrates, consistent with an immune evasive tumor microenvironment. We show that major oncogenic isoforms of WT1 are overexpressed in primary KS tissue and observed WT1 upregulation upon de novo infection of endothelial cells with KSHV. KSHV latent viral FLICE-inhibitory protein (vFLIP) upregulated total and major isoforms of WT1, but upregulation was not seen after expression of mutant vFLIP that is unable to bind IKKƴ and induce NFκB. siRNA targeting of WT1 in latent KSHV infection resulted in decreased total cell number and pAKT, BCL2 and LANA protein expression. Finally, we show that ESK-1, a T cell receptor-like monoclonal antibody that recognizes WT1 peptides presented on MHC HLA-A0201, demonstrates increased binding to endothelial cells after KSHV infection or induction of vFLIP expression. We propose that oncogenic isoforms of WT1 are upregulated by KSHV to promote tumorigenesis and immunotherapy directed against WT1 may be an approach for KS treatment.

Case Report: A Primary Right Ventricular Vascular Malformation Presenting as a Mass

Primary right ventricular vascular malformation is a rare primary benign anomaly in heart in nature. Due to the extremely low incidence and the progress on the classification of vascular malformation, a few cases were reported in the literatures. In the current case study, a 55-year-old women presented with a cardiac mass that was identified in right ventricle during a routine medical checkup. Magnetic resonance imaging demonstrated a well-circumscribed mass attached to the interventricular septum. Median sternotomy for the surgical resection of the mass and a cardiopulmonary bypass were performed. The intraoperative transesophageal echocardiogram showed that the mass had been successfully removed. The patient recovered well and was discharged from hospital 9 days after the surgery. The pathological diagnosis was primary cardiac arteriovenous malformation. No mass recurrence was shown by echocardiography during the 13 months' follow-up.

Angiogenesis pattern and H3.3 histone mutation in aggressive and non-aggressive central giant cell lesions

OBJECTIVE

The aim of this study was to evaluate angiogenesis in central giant cell lesions (CGCL) and its association with biological behavior. In addition, investigation of the histone H3.3 mutation was performed.

DESIGN

Thirty-eight cases of CGCL were classified as aggressive (n = 9) or nonaggressive (n = 29). Cases were submitted to immunohistochemistry to compare angiogenesis using Wilms' tumor protein 1 (WT1), platelet endothelial cell adhesion molecule (CD31) and endoglin (CD105) between groups. To verify the presence of genic mutation, histone H3.3 was investigated.

RESULTS

WT1 was expressed in mononuclear and giant cells of all cases. CD31 and CD105 were expressed in CGCL microvessels, with a higher CD105 microvascular density than CD31. No statistically significant difference was observed between groups. None of the cases studied showed the histone mutation.

CONCLUSIONS

There was no difference between aggressive and nonaggressive lesions regarding the angiogenic markers. The expression of WT1 and CD105 suggests that CGCL presents a tumoral vascular pattern with high neoangiogenic activity. The absence of histone mutation may indicate that CGCL is not a true giant cell tumor.

Wilms' Tumor 1 (WT1): A Novel Immunomarker of Dermatofibrosarcoma Protuberans-An Immunohistochemical Study on a Series of 114 Cases of Bland-Looking Mesenchymal Spindle Cell Lesions of the Dermis/Subcutaneous Tissues

Simple Summary

Dermatofibrosarcoma protuberans (DFSP) is a superficial fibroblastic spindle cell sarcoma with a high rate of local recurrence (20% to 50%) but with a low metastatic potential. DFSP is characterized by COL1A1-PDGFB gene fusion and diffuse immunohistochemical expression of CD34. This immunomarker is especially useful in distinguishing DFSP from its morphological mimickers, especially when pathologists are faced with small biopsies. Apart from CD34, there are no additional diagnostic immunomarkers for DFSP, and thus, there is the need to identify more sensitive and specific markers for this sarcoma. Recently, Wilms’ tumor 1 (WT1) has been shown to be diffusely expressed in the cytoplasm of several benign and malignant mesenchymal spindle cell lesions. Based on this background, the aim of this study is to evaluate the immunohistochemical expression of WT1 protein in a series of bland-looking spindle cell lesions of the dermis/subcutis, emphasizing its potential diagnostic role in identifying DFSP among its morphological mimickers.

Abstract

Purpose: to investigate the immunohistochemical expression and distribution of Wilms’ tumor 1 (WT1) (transcription factor produced by the tumor suppressor gene of the same name) in a series of 114 cases of bland-looking mesenchymal spindle cell lesions of the dermis/subcutaneous tissues to establish whether this immunomarker is differentially expressed in dermatofibrosarcoma protuberans (DFSP) versus its potential morphological mimickers. Methods: This retrospective multi-centric immunohistochemical study included 57 DFSP cases, 15 dermatofibromas, 5 deep fibrous histiocytomas, 8 neurofibromas, 5 spindle cell lipomas, 8 dermal scars, 6 nodular fasciitis, 5 cutaneous leiomyomas and 5 solitary fibrous tumors. Among the 57 DFSP cases, 11 were recurrent lesions; 2 non-recurrent cases exhibited an additional “fibrosarcomatous” overgrowth and 1 recurrent and 2 primary tumors contained a minority of “giant cell fibroblastoma” components. Results: Most DFSP (95% of cases) exhibited cytoplasmic staining for WT1; 11/11 residual/recurrent tumors showed diffuse and strong WT1 cytoplasmic immunoreactivity; apart from neurofibromas, WT1 expression was lacking in all the other cases studied. Conclusions: The cytoplasmic expression of WT1 may be exploitable as a complementary diagnostic immunomarker to CD34 in confirming the diagnosis of DFSP and to better evaluate the residual/recurrent tumor component.

Intravascular Lobular Capillary Hemangioma (Intravascular Pyogenic Granuloma): A Clinicopathologic Study of 40 Cases

Intravascular lobular capillary hemangioma (ILCH), or intravascular pyogenic granuloma, is relatively rare and likely underrecognized. We reviewed all ILCH cases from our institution confirmed pathologically from 2006 to 2019. Immunostains for smooth muscle actin and Wilms tumor 1 were performed on all cases and prior immunohistochemical stains were reviewed. Forty cases were identified (22 females; 18 males) with a median age of 53 years (range: 13 to 85 y). Clinically, all were well-circumscribed, stable to slow-growing raised/cystic skin lesions ranging from 1 to 40 mm. Most were located on the upper extremities (n=18), followed by head and neck (n=16). Vascular lesions were suspected clinically in one third. Of the consultation cases, provided differential diagnoses included Masson tumor, other hemangiomas, and vascular tumors of intermediate malignancy. The common histologic features were a well-circumscribed, lobular proliferation of closely packed capillaries with central ectatic vessels. The surrounding vascular wall was well-visualized in only half of the cases. About 30% of the cases were mitotically active (mean: 8 to 9 mitotic figures/10 HPFs), and 34% showed mild to moderate cytologic atypia. Hobnail features were present in 40% of cases. All cases were diffusely and strongly positive for Wilms tumor 1. Smooth muscle actin stains highlighted pericytes in all cases. Of the 20 cases with clinical follow-up (median: 40 mo), none recurred. ILCH commonly involves the upper extremities and a vascular tumor is suspected clinically in the minority. Mitotic activity and cytologic atypia, when present, can cause confusion with more aggressive vascular tumors. Recognition of this entity is essential as it is a benign lesion with no risk of recurrence following limited local excision.

Papillary Endothelial Hyperplasia (Masson Tumor) of the Hand. Surgical and Pathological Consideration from Seven Cases Using New Vascular Markers

Although papillary endothelial hyperplasia may occur at almost any site, one of the most common sites is the hand. It is generally regarded as a reactive vascular proliferation i.e. exuberant form of organizing thrombus. Diagnosis of Masson tumor can be challenging due to its close clinical, radiological and even histopathological resemblance to angiosarcoma. We present seven cases of Masson tumor of the hand; wanting to reveal its nature using new vascular markers and discuss the treatment options and expected outcomes, present clinical and radiological features that may aid diagnosis and also offer treatment plans. A multicenter retrospective study was performed between January 2014 and November 2019. Immunohistochemical stains of Glut1, WT1, ERG, CD31 and alpha smooth muscle actin (ASMA) were performed on each cases. We found seven cases during the examined period. 4 out of 7 cases were women. All lesions occurred in the hands. 3 out of 7 cases appeared in a previously present vascular malformation. All cases were treated with surgical excision and the diagnosis of papillary endothelial hyperplasia was made by histology. Pre-operative testing (radiograph/MRI/US/fine needle aspiration biopsy) did not suggest the diagnosis of Masson tumor; however, aspiration cytology could rule out malignancy. The proliferative endothelial cells proved to be Glut1 negative and WT1 positive and the accompanying pericytic cells were ASMA positive in all cases. Though Masson tumor is a rare vascular lesion in the hand among other vascular tumors, it should be considered in the differential diagnostics even in the case of previously existing vascular malformation. WT1 positivity of the endothelial cells and the accompanying pericytic cells raises the question whether the initially reactive endothelial proliferation may transform into a true benign vascular tumor.

CD10 and CD34 as markers in vascular malformations with PIK3CA and TEK mutations

AIMS

Vascular malformations (vMs) encompass a wide range of diseases often associated with somatic or, more rarely, germinal genetic mutations. A mutation in the PIK3Ca/mTOR pathway is more often involved in various vMs. CD10 and CD34 are cellular markers that may play a role in mesenchymal differentiation and proliferation. The aim of our study was to find a possible link between the immunohistochemical expression of CD10 and CD34 in vMs and their relationship with mutations in the PIK3CA/mTOR signaling pathway.

METHODS AND RESULTS

Our study on 58 samples of vMs showed that in endothelial cells, CD10 was significantly expressed in PIK3CA-mutated samples compared with samples without any mutation (p < 0.05), especially and even more consistently when compared with samples with mutation in other pathways (p < 0.0001). Conversely, in the same PIK3CA-mutated samples, CD34 expression in endothelial cells was significantly reduced compared with samples either without any mutation or mutations in other pathways (p < 0.05 and p < 0.0005). Compared with samples with mutations in other pathways, a significant overexpression of endothelial CD10 was also found in samples with TEK/TIE2 mutation, a gene linked to the PIK3CA/mTOR pathway (p < 0.01). However, CD34 expression was not altered. In samples with PIK3CA mutation, the CD10 expression was significantly increased in the stroma compared with samples with TEK/TIE2 gene or other gene mutations (p < 0.05).

CONCLUSION

Therefore, the CD10 and CD34 immunohistochemical profile could suggest/support the presence of mutations in the PIK3CA/mTOR pathway in samples of vMs.

Eccrine angiokeratomatous hamartoma combined with solitary angiokeratoma or verrucous venous malformation: Report of two cases and comprehensive review of the literature

First reported in 2006, eccrine angiokeratomatous hamartoma is a very rare vascular malformation of the skin, with only few described cases. It has a peculiar histopathology with features deriving from the combination of two different vascular malformations of the skin: solitary angiokeratoma and eccrine angiomatous hamartoma. In the past, other authors described similar hamartomatous lesions with features deriving from verrucous venous malformation and eccrine angiomatous hamartoma. We believe that these lesions are clearly overlapping from clinical, histopathological, and immunohistochemical points of view and the term "eccrine angiokeratomatous hamartoma" should be used to indicate the whole spectrum of these lesions as suggested by Kanitakis et al. Herein we present two cases of this rare vascular hamartoma, with clinical, histopathological and immunohistochemical characterization. In addition, for the first time we report a complete and detailed review of the literature to clarify the clinical, epidemiological, and histopathological features of this unique entity.

Immunohistochemical Expression of Wilms’ Tumor 1 Protein in Human Tissues: From Ontogenesis to Neoplastic Tissues

The human Wilms’ tumor gene (WT1) was originally isolated in a Wilms’ tumor of the kidney as a tumor suppressor gene. Numerous isoforms of WT1, by combination of alternative translational start sites, alternative RNA splicing and RNA editing, have been well documented. During human ontogenesis, according to the antibodies used, anti-C or N-terminus WT1 protein, nuclear expression can be frequently obtained in numerous tissues, including metanephric and mesonephric glomeruli, and mesothelial and sub-mesothelial cells, while cytoplasmic staining is usually found in developing smooth and skeletal cells, myocardium, glial cells, neuroblasts, adrenal cortical cells and the endothelial cells of blood vessels. WT1 has been originally described as a tumor suppressor gene in renal Wilms’ tumor, but more recent studies emphasized its potential oncogenic role in several neoplasia with a variable immunostaining pattern that can be exclusively nuclear, cytoplasmic or both, according to the antibodies used (anti-C or N-terminus WT1 protein). With the present review we focus on the immunohistochemical expression of WT1 in some tumors, emphasizing its potential diagnostic role and usefulness in differential diagnosis. In addition, we analyze the WT1 protein expression profile in human embryonal/fetal tissues in order to suggest a possible role in the development of organs and tissues and to establish whether expression in some tumors replicates that observed during the development of tissues from which these tumors arise.

Verrucous venous malformations of the hand

Verrucous venous malformation is a rare vascular anomaly that presents as a deep purple skin stain and evolves into a larger scaly, keratotic lesion that can bleed and cause pain. Because of its similarity to other vascular lesions, it is often misdiagnosed and treated incorrectly. Ten patients with hand verrucous venous malformations evaluated between 1990 and 2017 were reviewed. Diagnosis was confirmed with histopathology. Six patients were initially misdiagnosed and two patients were incorrectly treated. Eight patients had excision procedures. Immunostaining for glucose transporter 1 protein was positive in all specimens that underwent staining. Most (three of four) of the patients with isolated small lesions remained disease free postoperatively, but those with larger lesions experienced recurrence or continued growth. Early recognition of verrucous venous malformation is important because nonsurgical ablative techniques are ineffective; the optimal treatment is surgery. Level of evidence: IV.

Acquired Elastotic Hemangioma: A Case Report and Review of 49 Previously Reported Cases

In the past decades, there was a considerable advance in regard to recognition of morphologic findings and classification of several benign and malignant vascular proliferations. In 2002, attention was called by Requena et al to a new variant of cutaneous hemangioma named acquired elastotic hemangioma. In this article, a case of acquired elastotic hemangioma is reported with documentation of clinical, dermatoscopic, histopathological, and immunohistochemical findings. A systematic review of the previously 49 reported cases is provided. The criteria for clinical and histopathological diagnosis are highlighted.

Angioma serpiginosum: a case report and review of the literature

Background

Angioma serpiginosum is a rare vascular anomaly whose pathogenesis is still unknown. It is characterized by the onset of vascular reddish macules and papules during childhood, lesions are usually monolateral with a linear serpiginous pattern. It is rarely associated with extracutaneous findings. This entity has not yet been included in the classification of the International Society for the Study of Vascular Anomalies.

Case presentation

We describe the first Italian report of angioma serpiginosum with a congenital symmetrical presentation. The patient had a further extension of macules during puberty involving both of the soles. No extracutaneous manifestations were present. Diagnosis was confirmed with dermoscopy and light microscopy that revealed the typical clusters of dilated, thickened and PAS+ capillaries in the upper dermis. Moreover, Immunohistochemistry showed positive WT-1 staining. Genetic analysis with next generation sequencing did not detected any mutation.

Conclusions

Our patient presented a peculiar symmetrical and planar extension with a serpiginous linear pattern. The proliferative nature of this condition has been widely discussed in literature. In our case immunohistochemistry was positive for Wilms tumor-1, a new endothelial marker expressed during angiogenesis in reparative processes and endothelial tumors.

Clinical evolution, histological and immunohistochemical findings suggest that angioma serpiginosum should be considered as a vascular proliferation. For these reasons we think it should be included in the international classification as a tumor.

Verrucous hemangioma (also known as verrucous venous malformation): A vascular anomaly frequently misdiagnosed as a lymphatic malformation

Verrucous hemangioma or verrucous venous malformation is a superficial venous malformation frequently misdiagnosed as a lymphatic malformation because of its classical hyperkeratotic appearance. Clinical characteristics of VVM were studied in patients with a histologically confirmed VVM, and validated in a prospective study of 18 patients. VVM was made of separated vascular elements with irregular shape, in a linear disposition, with variable thickness and keratosis. Its specific vascular pattern consisting of an erythematous patch with scattered small red to violet dots was easily identified using dermoscopy. In many cases, the typical clinical presentation of verrucous hemangioma is sufficient to establish the diagnosis and a biopsy may not be required.

[Venolymphatic malformation with bone erosion. An unusual affectation in these lesions]

A 30 year old male presented with a cutaneous lesion on the distal area of the 5th toe with involvement of the outer edges. Macroscopically, it was a 1cm violaceous and keratotic lesion. Radiography showed an increase in soft tissue, possibly due to a vascular lesion. MRI showed a hyper-intense signal with erosion of the distal phalanx compatible with a low-flow vascular malformation. The distal phalanx was amputated. Histopathology revealed a lesion formed by venous and D2-40 positive lymphatic vessels. This case highlights the fact that even minimal skin involvement in vascular malformations may conceal an important deeper lesion, such as erosion of the cortical bone.

Nonepithelial Tumors and Tumor-like Lesions of the Skin and Subcutis in Children

This overview of mesenchymal tumors presenting in the skin and/or subcutis in children brings together the range of neoplasms and hamartomas which are seen in this age-group. It is not surprising from the perspective of the pediatric or general surgical pathologist that vascular anomalies, including true neoplasms and vascular malformations, are the common phenotypic category. Since there is considerable morphologic overlap among these lesions, clinicopathologic correlation may be more important than for many of the other mesenchymal tumors. The skin and subcutis are the most common sites of clinical presentation for the infantile myofibroma which is the most common of fibrous mesenchymal tumors in children. Several of the other mesenchymal tumors are more common adults-like dermatofibrosarcoma protuberans, but nonetheless have an important presence in children, even as a congenital neoplasm. A lipomatous tumor in a young child should be considered as a possible manifestation of an overgrowth syndrome.

Angiosarcoma of the Pelvis in a 13-Year-Old Girl

Angiosarcomas are highly aggressive malignancies of vascular origin and are very rarely found in children. We report a case of a 13-year-old girl with a history of abdominal pain and increased abdominal girth. Radiologic imaging showed significant ascites and large pelvic masses involving bilateral adnexa with abdominal spread. Microscopic examination of a biopsy revealed pleomorphic epithelioid and spindle cells with brisk mitotic activity, intracytoplasmic vacuoles, vascular channels, and large areas of hemorrhage and necrosis. Immunohistochemistry analysis showed strong and diffuse positivity for CD31, D2-40, ERG, FLI-1, and focally for CD34, vWF, and EMA. The diagnosis of metastatic angiosarcoma was rendered. The patient was treated aggressively with systemic chemotherapy, immunotherapy, cytoreductive surgery, and hyperthermic intraperitoneal chemotherapy, with a favorable response after 1-year follow-up. Angiosarcoma should be considered when encountering a vascular tumor with pleomorphism, brisk mitotic activity, and necrosis. Immunohistochemistry studies are necessary for proper diagnosis.

Phosphoinositide 3-kinase: a new kid on the block in vascular anomalies

Vascular anomalies are broadly divided into vascular tumours and malformations. These lesions are composed of abnormal vascular elements of various types, and mainly affect infants, children, and young adults. Vascular anomalies may be painful, may be complicated by bleeding, infection, or organ dysfunction, and can have secondary effects on other tissues. Current treatment strategies include surgical excision, pulsed laser, and sclerotherapy, which are invasive, with risks of recurrence. There are growing pharmacological options for these vascular anomalies, but, to date, no specific targeted therapies have been developed. Phosphoinositide 3-kinases (PI3Ks) constitute a family of lipid kinases that are involved in signal transduction and vesicular traffic, and that modulate important cellular processes such as proliferation, growth, and migration. Recent findings have indicated that the PI3K signalling pathway is important in the pathogenesis of vascular anomalies. This provides an opportunity to use PI3K inhibitors, which are in clinical trials for cancer treatment, for such lesions. Here, we provide an update on the classification of vascular anomalies, with their major features, and discuss the role of the PI3K signalling pathway in the pathogenesis of vascular anomalies, and their clinical implications and therapeutic opportunities. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Classification of vascular malformations

With the term „hemangioma” different vascular anomalies are described. Here one has to discriminate the congenital vascular tumours from the vascular anomalies. But for a clear indication a definite classification is necessary. Basis is the actual ISSVA classification. In the latest version they have incorporated the embryological aspects of the Hamburg Classification. Especially in the vasculogenetic (″extratruncular″) malformations one found increasing genetic defects. Here is an overlap to the neuro-ectodermal syndromes. By this, common therapeutic strategies are in progress.

Intravascular Myopericytoma of the Plantar Region: Case Report and Discussion of the Probable Origin From a Cutaneous Vascular Malformation

Myopericytoma is a perivascular myoid neoplasm of skin and soft tissues characterized by numerous thin-walled blood vessels surrounded concentrically by round to spindle myoid tumor cells, which shows α-smooth muscle actin and h-caldesmon coexpression and commonly negativity for desmin. These tumors arise predominantly in extremities of adult patients with benign clinical course. Based on the architectural pattern, there are various histologic variants as classical-solid myopericytoma, hemangiopericytoma-like myopericytoma, angioleiomyoma-like myopericytoma, myofibroma-like myopericytoma, hipocelular fibroma-like myopericytoma, intravascular myopericytoma, cellular immature myopericytoma, and malignant myopericytoma. The authors report a case that fully satisfies the morphological and immunohistochemical criteria for intravascular myopericytoma, which plantar location is not previously described in the literature. In addition, the authors discuss about its possible development from a preexistent cutaneous vascular malformation.

Unusually Large Patch-Type Noninvoluting Congenital Hemangioma of the Shoulder: A Report of Two Cases

Noninvoluting congenital hemangiomas (NICHs) are vascular tumors that are fully formed at birth and do not regress. Clinically, NICHs persist indefinitely over time. Histologically they are characterized by deep dermal lobules of small vessels with endothelial cells that do not stain with glucose transporter 1 (GLUT1). Two similar cases of unusually large, patch-type NICHs of the shoulder in neonates were observed in the past 20 years in two pediatric dermatology units in Italy. In both cases, histopathology showed lobular collections of small vessels that did not stain with GLUT1. The clinical features of the two cases remained unchanged over a follow-up period of 10 and 4 years, respectively. The large size and flat appearance of the lesions could be due to their early onset during embryogenesis.

Wilms' tumor 1 (WT1) protein expression in human developing tissues

Several genes playing crucial roles in human development often reproduce a key role also during the onset and progression of malignant tumors. WT1, a transcription factor expressed with a dynamic pattern during human development, has either oncogenic or suppressor tumor properties. A detailed analysis of the immunohistochemical profile of WT1 protein in human developmental tissues could be exploitable as the rational for better understanding its role in cancerogenesis and planning innovative WT1-based therapeutic approaches. This review focuses on the dynamic immunohistochemical expression and distribution of WT1 protein during human ontogenesis, providing illustrations and discussion on the most relevant findings. The possibility that WT1 nuclear/cytoplasmic expression in some tumors mirrors its normal developmental regulation will be emphasized.

Oncofetal expression of Wilms' tumor 1 (WT1) protein in human fetal, adult and neoplastic skeletal muscle tissues

There is increasing evidence that WT1 protein expression is found not only at nuclear, but also at cytoplasmic, level in several developing and neoplastic tissues. In order to better understand the possible role of WT1 protein in human skeletal myogenesis and oncogenesis of rhabdomyosarcoma, we assessed immunohistochemically its comparative expression in a large series of human developing, adult and neoplastic skeletal muscle tissues. The present study shows that WT1 protein is developmentally expressed in the cytoplasm of human myoblasts from the 6 weeks of gestational age. This expression was maintained in the myotubes of developing muscles of the trunk, head, neck, and extremities, while it was down-regulated in fetal skeletal fibers from 20 weeks of gestational age as well as in adult normal skeletal muscle. Notably, WT1 immunostaining disappeared from rhabdomyomas, whereas it was strongly and diffusely re-expressed in all cases (27/27) of embryonal and alveolar rhabdomyosarcoma. The comparative evaluation of the immunohistochemical findings revealed that WT1 cytoplasmic expression in rhabdomyosarcoma may represent an ontogenetic reversal, and this nuclear transcription factor can also be considered an oncofetal protein which can be exploitable as an additional, highly sensitive immunomarker, together with desmin, myogenin and MyoD1, of this tumor. Moreover, our observations support the rationale for the use of WT1 protein-based target therapy in high risk rhabdomyosarcomas in children and adolescents.

Immunohistochemistry in dermatopathology

CONTEXT

Immunohistochemistry is not a diagnostic test but a highly valuable tool that requires interpretation within a context.

OBJECTIVE

To review the current status and limitations of immunohistochemistry in dermatopathology.

DATA SOURCES

English-language literature published between 1980 and 2014.

CONCLUSIONS

Although immunohistochemistry is rarely completely specific or sensitive, it is an important adjunctive technique in dermatopathology and can be helpful in a series of diagnostic dilemmas.

WT1 regulates angiogenesis in Ewing Sarcoma

Angiogenesis is required for tumor growth. WT1, a protein that affects both mRNA transcription and splicing, has recently been shown to regulate expression of vascular endothelial growth factor (VEGF), one of the major mediators of angiogenesis. In the present study, we tested the hypothesis that WT1 is a key regulator of tumor angiogenesis in Ewing sarcoma. We expressed exogenous WT1 in the WT1-null Ewing sarcoma cell line, SK-ES-1, and we suppressed WT1 expression using shRNA in the WT1-positive Ewing sarcoma cell line, MHH-ES. Suppression of WT1 in MHH-ES cells impairs angiogenesis, while expression of WT1 in SK-ES-1 cells causes increased angiogenesis. Different WT1 isoforms result in vessels with distinct morphologies, and this correlates with preferential upregulation of particular VEGF isoforms. WT1-expressing tumors show increased expression of pro-angiogenic molecules such as VEGF, MMP9, Ang-1, and Tie-2, supporting the hypothesis that WT1 is a global regulator of angiogenesis. We also demonstrate that WT1 regulates the expression of a panel of pro-angiogenic molecules in Ewing sarcoma cell lines. Finally, we found that WT1 expression is correlated with VEGF expression, MMP9 expression, and microvessel density in samples of primary Ewing sarcoma. Thus, our results demonstrate that WT1 expression directly regulates tumor angiogenesis by controlling the expression of a panel of pro-angiogenic genes.

Benign lymphangioendothelioma presenting as a giant flank mass

Benign lymphangioendothelioma is a rare lesion of controversial etiology and a histopathologic mimic of Kaposi sarcoma and so-called 'well-differentiated' angiosarcoma. Its most typical clinical presentation is as a slowly expanding, erythematous patch or plaque; it rarely presents as a large mass. We report the second case of a giant benign lymphangioendothelioma, which arose as a serpiginous mass involving most of the flank of an elderly male with no prior radiation exposure and with a remote history of herpes zoster infection. A biopsy revealed numerous anastomosing vascular channels extending from the superficial dermis to the subcutis that were dilated to progressively slit-like in architecture. The endothelial cells lacked cytologic atypia, hobnailing, or significant mitotic activity, and human herpesvirus-8 expression was absent. Positivity for podoplanin (D2-40) was observed in the endothelial cells, supporting a lymphatic phenotype. Furthermore, the lesional cells lacked immunohistochemical expression of Wilms tumor 1, providing further support of a malformative - rather than neoplastic - pathogenesis.

Vascular malformations that were diagnosed as or accompanied by malignant tumors

BACKGROUND

Vascular malformations can mimic malignant tumors, and the coexistence of both types of lesions can limit and interfere with treatment. A consecutive series of vascular malformations that were treated and evaluated in a single institute and cases involving vascular anomalies combined with malignancies or malignancies that were treated as vascular anomalies were analyzed.

OBJECTIVE

Absolute ethanol is used in the treatment and management of vascular malformations and is sometimes administered before a definitive diagnosis has been obtained, despite the fact that some vascular lesions are subsequently revealed to be malignant tumors. This study discusses such cases.

MATERIALS AND METHODS

From January 2006 to August 2012, 139 patients were treated for vascular malformations at Nagasaki University Hospital and were followed up for a minimum of 1 year.

RESULTS

Four malignant lesions coexisted with or were misdiagnosed as vascular malformations, including a malignant peripheral nerve sheath tumor located in the chest, a hemangiopericytoma of the palate, an adenoid cystic carcinoma of the cheek, and a squamous cell carcinoma of the cheek. Thus, malignant lesions were detected in 2.88% of cases in which vascular malformations were preoperatively diagnosed.

CONCLUSION

When treating vascular malformations, it is advisable to be aware of the possibility of malignancy.

Cytoplasmic expression of Wilms tumor transcription factor-1 (WT1): a useful immunomarker for young-type fibromatoses and infantile fibrosarcoma

There is increasing evidence that Wilms' tumor transcription factor-1 (WT1) is expressed in the cytoplasm of neoplastic cells from different benign and malignant tumors. Only a few studies on WT1 cytoplasmic immunolocalization are available in pediatric tumors. The aim of the present study was to investigate immunohistochemically the expression and distribution of WT1 in a large series of soft tissue fibroblastic/myofibroblastic lesions occurring in children and adolescents. Notably WT1 was not expressed in nodular fasciitis and desmoid-type (adult) fibromatosis, while it stained diffusely and strongly in several infantile-type fibromatoses, such as fibrous hamartoma of infancy, myofibroma/myofibromatosis, and lipofibromatosis. Interestingly, WT1 cytoplasmic expression was also found in all cases (10/10) of infantile fibrosarcomas examined. The present study shows that a diffuse WT1 cytoplasmic expression is of complementary diagnostic value to conventional myofibroblastic markers (α-smooth muscle actin; desmin) in confirming diagnosis of young-type fibromatoses or infantile fibrosarcoma and in ruling out both desmoid-type fibromatoses and nodular fasciitis. WT1 cytoplasmic expression in infantile fibrosarcoma is a novel finding which could be exploitable as an immunomarker for this tumor. Although highly sensitive, WT1 cytoplasmic immunostaining is not specific for infantile fibrosarcoma, and thus it should be evaluated in the context of a wide immunohistochemical panel when pathologists are dealing with spindle cell lesions of soft tissues in children and adolescents. Accordingly we recommend that a correct diagnosis of fibroblastic/myofibroblastic soft tissue lesion in pediatric patients is usually achieved on the basis of a careful correlation of morphological and immunohistochemical findings in the appropriate clinical context. The different cellular localization of WT1, namely nuclear, cytoplasmic or nucleo-cytoplasmic, in different benign and malignant tumors supports the hypothesis that this transcription factor plays a complex role in tumorigenesis, likely as a chameleon protein functioning as either a tumor suppressor gene or an oncogene, depending on cellular context.

Wilms' tumor protein (WT1) in mammary myofibroblastoma: an immunohistochemical study

Wilms' tumor protein (WT1) has been immunohistochemically detected in the cytoplasm of some developing, adult normal and neoplastic human tissues, suggesting its complex regulator activity in transcriptional/translational processes. Among neoplastic tissues, WT1 has been documented in the cytoplasm of benign and malignant vascular tumors and in rhabdomyosarcoma, while there are no available studies about its expression in myofibroblastic tumors. Accordingly, we studied immunohistochemically the potential expression of WT1 in mammary myofibroblastoma (MFB), a prototypical myofibroblastic tumor. A series of 18 cases of mammary MFB, including several morphological variants (classic, fibrotic, myxoid, lipomatous, Schwannian-like, and epithelioid variants), were tested with antibodies against the N-terminal of WT1. The most striking finding was a diffuse and strong WT1 cytoplasmic immunostaining restricted to the "epithelioid cell MFB", a rare and diagnostically challenging variant. Conversely the other variants of MFB, including the classic-type, were negative or only focally positive. The present study shows that mammary epithelioid cell MFB should be added to the list of mesenchymal tumors which express WT1 in the cytoplasm of neoplastic cells. Accordingly, we suggest that the detection of WT1 cytoplasmic immunoreactivity is of complementary diagnostic value to conventional myofibroblastic markers in identifying epithelioid cell myofibroblastoma.

Cutaneous lymphatic malformation characterized by swelling of digits: a report of six cases

BACKGROUND

Cutaneous lymphatic malformations represent a group of heterogeneous diseases. In clinical practice, some cases of cutaneous lymphatic malformation have been found to differ from the well-characterized entities, and are difficult to classify.

OBJECTIVE

To report the clinical, histopathological and immunohistochemical characteristics of six cases of lymphatic malformation characterized by swelling of the digits.

METHODS

Six patients with swelling of the digits were included in this study. Histopathological examination and immunohistochemical staining of CD31, D2-40, Prox1, Wilms tumor 1 (WT-1) and human herpesvirus-8 (HHV-8) were performed for all cases.

RESULTS

All cases were congenital lesions and presented as swelling of single or multiple digits. Histopathologically, the lesions showed proliferation of small-to-medium-sized vessels in the dermis and subcutaneous tissue. These abnormal vessels were positive for CD31, D2-40 and Prox1, and negative for WT-1 and HHV-8.

CONCLUSION

The six cases reported herein represent a specific cutaneous lymphatic malformation different from previously reported entities.

Expression of Prox1, D2-40, and WT1 in spindle cell hemangioma

BACKGROUND

Spindle cell hemangioma is a benign vascular proliferation that usually occurs on acral sites. A recent report showed focal positive staining of Prox1 in spindle cell hemangioma.

METHODS

We performed an immunohistochemical study of spindle cell hemangioma with antibodies to CD31, D2-40, Prox1, smooth muscle actin (SMA) and Wilms tumor-1 (WT-1).

RESULTS

The endothelial cells in spindle cell hemangioma were positive for CD31 and Prox1, focally positive for D2-40 and negative for WT-1, whereas the myoid spindle cells around the endothelial cells were weakly positive for WT-1.

CONCLUSION

Our results suggest that spindle cell hemangioma is a lymphatic malformation.

Benign lymphangioendothelioma: a clinical, histopathologic and immunohistochemical analysis of four cases

BACKGROUND

Benign lymphangioendothelioma represents a rare lymphatic vascular proliferation characterized by proliferation of irregular and thin-walled vessels dissecting amongst dermal collagen. Immunohistochemical analysis has been lacking in most previously reported cases.

METHODS

Herein, we report the clinical and histopathologic characteristics of four cases of benign lymphangioendothelioma. Immunohistochemical study was completed for all lesions.

RESULTS

All lesions presented as large, red to brown patches or plaques. Three lesions were located on the thigh and one lesion was located on the neck. Histopathologically, all lesions showed proliferation of anastomotic or retiform thin-walled vessels with a single layer of endothelial cells that dissect the dermis. D2-40 and Prox1 immunostains were positive and Wilms tumor 1 (WT-1) immunostain was negative in all cases.

CONCLUSION

Benign lymphangioendothelioma represents a lymphatic vascular proliferation. A lack of expression of WT-1 suggests it represents a lymphatic vascular malformation.

Microvenular hemangioma presenting with numerous bilateral macules, patches, and plaques: a case report and review of the literature

Microvenular hemangioma (MVH) is a rare, slowly growing, benign vascular tumor that typically presents as a solitary enlarging plaque or nodule on the trunk or the extremities of young to middle-aged adults. A minority of MVH present with multiple lesions that are either gradually or suddenly acquired (eruptive MVH). Herein, we report a case of a 53-year-old woman who progressively developed numerous bilateral MVHs presenting as enlarging, blanching, erythematous to violaceous macules, patches, and plaques over the proximal thighs and axillae. Two biopsies exhibited the irregular branching venules with inconspicuous lumina lacking endothelial atypia and associated with dermal fibrosis characteristic of MVH. Immunophenotypically, the endothelium expressed Wilms Tumor 1, CD31, CD34, and erythrocyte-type glucose transporter protein (GLUT-1) GLUT-1 focally and was negative for Human herpes virus 8 and the lymphatic marker D2-40. In addition, numerous dermal spindle cells expressing CD34 and procollagen, putative fibrocytes, surrounded the thickened dermal collagen bundles and small vessels of MVH implicating a reactive/reparative (proliferative) process due to an unrecognized cutaneous injury. A review of MVH summarizing its clinicopathologic findings and its natural history is presented.

Solitary angiokeratoma on palms and soles: a clinicopathological analysis of 21 cases

Angiokeratoma includes a group of unrelated diseases characterized by hyperkeratosis and dilation of vessels in the superficial dermis. In this study, 21 cases of solitary lesions located on palms and soles and histopathologically diagnosed as angiokeratoma were analyzed retrospectively. All lesions presented as red to violet macules or plaques. Histopathologically, all of them showed hyperkeratosis and vascular dilation in the papillary to deep dermis. The elongated vessels were of different sizes and shape, lined by a single layer of endothelial cells. In 13 lesions, the endothelial cells protruded into the lumen, forming a hobnail appearance. Immunohistochemical study showed the endothelial cells were positive for CD31 and CD34, negative for D2-40, and focally positive for Wilms tumor 1 (WT-1) in most cases. Our cases represented a rare type of angiokeratoma located on the palms and soles, in which the focal positivity of WT-1 was different from previously reported vascular proliferations.

Invasive lymphatic malformation (gorham-stout) of the pelvis with prominent skin involvement

Gorham-Stout syndrome is a rare disease characterized by progressive osteolysis leading to disappearance of the bone. Vascular proliferations have been implicated in the pathogenesis of this syndrome. The case of a 7-year-old girl with a prominent invasive lymphatic malformation on the lumbosacral area and massive osteolysis of the pelvic girdle is reported.

Genotypes and phenotypes of 162 families with a glomulin mutation

A decade ago, we identified a novel gene, glomulin (GLMN) in which mutations cause glomuvenous malformations (GVMs). GVMs are bluish-purple cutaneous vascular lesions with characteristic glomus cells in the walls of distended venous channels. The discovery of the genetic basis for GVMs allowed the definition of clinical features to distinguish GVMs from other venous anomalies. The variation in phenotype was also highlighted: from a single punctate blue dot to a large plaque-like lesion. In this study, we screened GLMN in a large cohort of patients to broaden the spectrum of mutations, define their frequency and search for possible genotype-phenotype correlations. Taking into account 6 families published by others, a mutation in GLMN has been found in 162 families. This represents 40 different mutations; the most frequent one being present in almost 45% of them. Expressivity varies largely, without a genotype/phenotype relationship. Among 381 individuals with a mutation, we discovered 37 unaffected carriers, implying a penetrance of 90%. As nonpenetrant individuals may transmit the disease to their descendants, knowledge on the mutational status is needed for appropriate genetic counseling.