Pseudomyogenic (epithelioid sarcoma-like) hemangioendothelioma: characterization of five cases

Primary vascular tumors of bone: A comprehensive literature review on classification, diagnosis and treatment

Primary vascular tumors of bone are a heterogeneous group of neoplasms, ranging from benign hemangiomas to frankly malignant epithelioid hemangioendotheliomas and angiosarcomas. Over the years, their classification has been a matter of discussion, due to morphologic similarities and uncertainty regarding biologic behavior. Over the past decade, with the development of next-generation sequencing, there has been a significant improvement in the molecular characterization of these lesions. The integration of their morphologic, immunohistochemical and molecular features has led to a better stratification, with important prognostic and therapeutic implications. Nevertheless, primary vascular bone tumors still represent a challenge for medical oncologists. Given their rarity and heterogeneity, in the last few years, there has been no significant progress in medical treatment options, so further research is needed. Here we present a review of the current knowledge regarding primary vascular tumors of the bone, correlating clinicopathologic features with tumor behavior and therapeutic approaches.

Spontaneously regressive multifocal bone pseudomyogenic hemangioendothelioma in a 17-year-old boy: a case report

Pseudomyogenic hemangioendothelioma (PMH) is a rare vascular tumor that occurs in young mostly male patients. Seventy percent of PMH cases are multifocal and 25% involve bones. PMH is an indolent tumor with mild local aggressiveness and an unclear pathology. Only two cases of spontaneous regressive bone PMH have been reported. Here, we report the case of a 17-year-old boy with a multifocal bone PMH diagnosed from a chronic pain in his left knee. The PMH affected the right scapula, both humeri, the right olecranon, the second metacarpal bone, the second and fourth right ribs, the thoracic and lumbar spine, the pelvic ring, the left and right femoral neck, and the left patella. Every lesion presented with a lobulated, lytic pattern, sometimes with a peripheral sclerotic rim. MRI showed a tissue lesion with a low intensity on T1-weighted sequences and high intensity on T2-weighted sequences. Enhancement of T1 gadolinium fat-saturated sequences was bright. After discussion, a national specialized board decided to actively monitor the patient and start general chemotherapy in the case of progression. The disease was stable at 3 and 6 months and showed signs of regression at 1 year, which was further confirmed at 2 years. CT scan and MRI highlighted a progressive filling of the tumor with cancellous bone and a regression of the tissue contingent. This case report highlights to a new therapeutic approach for indolent PMH that does not prevent further treatment in the case of progression.

Pseudomyogenic Hemangioendothelioma: A Case of a Solitary Lesion With a Very Indolent Clinical Course

Pseudomyogenic hemangioendothelioma (PMH), also known as epithelioid sarcoma-like hemangioendothelioma, is a rare epithelioid vascular neoplasm predominantly affecting young adult males at an average age of approximately 30 years. This tumor is rare; therefore, detailed information regarding this tumor is still lacking. Here, we report a case of a man in his 20s presenting with left foot pain for about one year. Imaging showed a 2-cm ovoid, cortically based lesion with a lytic defect of the cortex at the fifth metatarsal proximal shaft. Histologically, the lesion presented as an infiltrating proliferation of distinctly myoid-appearing spindled cells with eosinophilic cytoplasm and mildly atypical vesicular nuclei. Scant mitoses were identified with no areas of necrosis. Tumor cells exhibited strong, diffuse cytokeratin expression as well as CD31 and ERG. CD34 was positive in a few tumor cells, and integrase interactor 1 (INI1) retained nuclear expression. No reactivity for S100, desmin, smooth muscle actin (SMA), epithelial membrane antigen (EMA), and CD1a was present. Over half of the patients with PMH develop multifocal lesions, often involving several tissue planes; however, distant metastasis is very infrequent. This patient underwent curettage and internal fixation of the left fifth metatarsal and had no evidence of recurrence or distant metastasis after seven years of follow-up. Our case contributes to the growing knowledge of PMH and sheds light on the prognosis of these lesions.

Pseudomyogenic hemangioendothelioma: A misleading vascular tumor

Introduction

Pseudomyogenic hemangioendothelioma (PHE) is a rare vascular soft tissue tumor of intermediate malignancy. The aim of this study was to present a rare case of PHE in the back and to review its clinicopathological features, therapeutic modalities, evolutionary aspects and prognosis.

Case presentation

We report the case of a 21-year-old man who consulted for a multinodular mass at the scapula level, that increased in size within 2 months. An excisional surgery was performed. Macroscopic examination showed ulcerated centimetric nodules with a crusty surface. Microscopic examination showed a multinodular proliferation arranged in clusters, made of spindle cells or epithelioid cells with variable atypia. Immunohistochemical study showed the expression ofAE1-AE3, ERG and INI-1. There was no staining for EMA, CD34, and CD-31. The diagnosis of PHE was retained.

Discussion

PHE affects young adult males and usually develops in the extremities. Clinically, more than half of the patients present with local recurrence. Distant metastases have also been reported. Microscopically, PHE resembles a myoid tumor or epithelioid sarcoma because of the abundant eosinophilic cytoplasm and cell shape. Tumor cells express cytokeratin and inconsistently CD34 and CD31. Hence the need to complete the study of ERG and INI1 expression in all soft tissue epithelioid tumors. The translocation t(7;19)(q22; q13) as well as the expression of FOSB in immunohistochemistry allow to differentiate with epithelioid sarcoma. Surgery is the treatment option.

Conclusion

PHE is a confusing entity with several mesenchymal neoplasms that must be carefully differentiated. Data regarding age, sex, location, course, and recurrence are important for proper diagnosis.

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Pseudomyogenic hemangioendothelioma is a rare vascular tumor.

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It can be misdiagnosed with several mesenchymal neoplasms, importantly an epithelioid sarcoma which prognosis is poor.

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Local recurrence and late metastasis can occur, so a strict follow-up is mandatory.

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Wide excision is the treatment option.

Pseudomyogenic hemangioendothelioma with bone and soft tissue involvement with favorable response to pamidronate: a case report and systematic review of the literature

Pseudomyogenic hemangioendothelioma (PMH) can be a challenge for diagnosis and might be confused with other tumors, such as epithelioid sarcoma. Here we present a case and a systematic review of the literature to identify and discuss PMH treatment in primary bone involvement. A 25-year-old woman was referred for bone pain (10/10) in the left lower limb. Magnetic resonance imaging (MRI) showed multiple bone lesions (left femur, tibia, patella, ankle, and foot) with well-defined borders without signs of local aggressiveness. Positron Emission Tomography-Computed Tomography (PET-CT) showed multiple metabolic musculoskeletal lesions in the left lower limb. A CT scan-guided biopsy was performed. Histological and immunohistochemical findings confirmed the diagnosis of PMH. After treatment with intravenous pamidronate (90 mg/monthly), the patient had clinical improvement, mild pain 2/10 without the use of non-steroidal anti-inflammatory drugs or opiates. Follow-up was assessed by MRI and PET-CT. PET-CT showed metabolic resolution of most of the bone and muscular lesions and a significant improvement of the femoral lesion. MRI showed that the lesions in the left femur, tibia, and foot had a marked decrease in size without intravenous post-contrast enhancement and smaller lesions had disappeared. After a 3-year follow-up, PET-CT showed no metabolically active images. Literature review identified 31 records including 58 clinical cases of PMH with primary bone involvement and treatment description for qualitative analysis. Most lesions (69%) were treated by local excision or curettage. In addition, amputations were performed in a significant percentage of cases (20.7%). In the last years, mTOR inhibitors (n = 7) and anti-resorptive treatments (n = 4) were considered as alternative treatment options, especially in multifocal lesions.

Pseudomyogenic Hemangioendothelioma of the Talocalcaneal Coalition: A Case Report

Pseudomyogenic hemangioendothelioma is a rare soft tissue tumor most often found in the lower extremities and predominantly occurring in males. The talocalcaneal coalition is an anatomic anomaly that develops between the talus and calcaneus bones, can cause hindfoot pain and subtalar joint stiffness, and has a prevalence of less than 1%. We present what is to our knowledge the first case report of a 17-year-old male with pseudomyogenic hemangioendothelioma occurring within a talocalcaneal coalition. The patient was treated with local excision of the tumor and the coalition. His American Orthopaedic Foot & Ankle Society ankle/hindfoot score went from 70 preoperatively to 92 at 1 year postoperatively, and he has had no evidence of recurrence at 1 and 3 years postoperatively. These tumors have suggestive but not diagnostic computed tomography, magnetic resonance imaging, and histopathological findings, and they are associated with a uniquely characteristic immunophenotype, including immunochemical reactivity to CD31, FLi-1, INI-1, ERG, and FOSB. Primary treatment of pseudomyogenic hemangioendothelioma most often involves local excision (but can require amputation) and may include adjuvant radiotherapy and/or chemotherapy. It has a relatively favorable prognosis, with a moderate risk of local recurrence and a low risk of metastases. Because metastases have been reported many years after treatment, long-term follow-up is necessary.

A Case of Pseudomyogenic Hemangioendothelioma of the Lower Extremity

Pseudomyogenic hemangioendothelioma (PMH) is a rare vascular tumor and was recently recognized as a distinct entity. It has a predilection for young male adults and it frequently occurs in distal extremities. Although it is known to follow an indolent course, multi-focal presentation and local recurrence are common. PMH should be differentiated from epithelioid sarcoma, epithelioid hemangioendothelioma, dermatofibrosarcoma protuberans, and rhabdomyosarcoma. Its characteristic immunohistochemical staining pattern and recurrent translocation t(7:19)(q22:q13) are the basis for its diagnosis. Surgical excision is the mainstay treatment, although chemotherapy can be considered in non-operable patients. We present a rare case of a 40-year-old Korean male patient diagnosed with PMH through an excisional biopsy to facilitate the recognition PMH in the clinical practice.

Oral Pseudomyogenic Hemangioendothelioma: Case Report and Review of the Literature

Pseduomyogenic hemangioendothelioma (PMH) is a vascular neoplasm of intermediate biological potential first described by Hornick and Fletcher (Am J Surg Pathol 35:190-201, 2011). Despite its initial categorization as a malignant entity, PMH often demonstrates an indolent behavior profile, and thus was classified as a rarely metastasizing endothelial neoplasm in the 2013 WHO Classification of Tumors of Soft Tissue and Bone. It is a tumor primarily of skin and soft tissue, with most reported cases involving the trunk or extremities. To date, only one case of PMH involving the oral cavity has been reported. Herein, we present a case of PMH involving the mandibular gingiva and vestibule of a 33-year-old female and discuss the salient features of this entity.

Pseudomyogenic Hemangioendothelioma: Distinctive FDG PET/CT Findings With Numerous Multilayer Lesions in a Single Distal Extremity

Pseudomyogenic hemangioendothelioma is a rare vascular tumor described as a fibroma-like variant of epithelioid sarcoma. There were scant publications about FDG PET/CT findings of pseudomyogenic hemangioendothelioma. A 20-year-old man with biopsy-confirmed pseudomyogenic hemangioendothelioma of the left tibia had FDG PET/CT for evaluation of the lesion extent and metastasis, which demonstrated numerous, multilayer FDG-avid lesions of the left lower extremity below the knee. Although pathologic examination is mandatory for diagnosis, FDG PET/CT of the case showed distinctive image finding of pseudomyogenic hemangioendothelioma: multifocal and multilayer lesions in a single distal lower extremity.

The clinicopathological spectrum of pseudomyogenic hemangioendothelioma: report of an additional series with review of the literature

We present here our experience with 24 cases of pseudomyogenic hemangioendothelioma (PMHE) to further delineate its clinicopathological spectrum. There were 18 males and 6 females with a median age of 28 years (range 10~64 years). Most patients presented with erythematous nodules or papules, with or without pain. The majority (63%) occurred in the lower extremities, whereas a minority involved the trunk (25%), upper extremities (8%), and head and neck (4%). Six cases (25%) had a primary bone origin. With physical and radiological examinations, 16 cases (67%) manifested as multifocal disease, involving multiple tissue planes or different bones within the anatomic region. Six cases (25%) involved skin, soft tissue, and bone simultaneously. Histologically, all cases showed features consistent with a PMHE characterized by loose fascicles or sheets of plump spindled to epithelioid cells harboring brightly eosinophilic cytoplasm and vesicular nuclei. In addition, five cases (21%) contained a prominent myxoid matrix, and one case displayed perineural and intravascular invasion. The follow-up information available in 18 patients revealed local recurrence in 4 patients (22%) and persistent disease in 8 patients (44%), respectively. One patient developed bilateral pulmonary metastases which showed significant remission after systemic chemotherapy. None of the patients died of the disease. As the clinical appearance of PMHE can be deceptive, a radiological examination is essential in identifying an insidious multifocal disease. Although PMHE has a predilection for the distal extremities of young males, this rare tumor type could also occur in unusual sites and affect middle-aged adults of both genders. The striking myoid appearance in association with myxoid stromal change may represent a potential diagnostic pitfall. Biologically, PMHE has an indolent clinical behavior, albeit metastatic disease may occur in rare instance.

Expanding the Spectrum of Genetic Alterations in Pseudomyogenic Hemangioendothelioma With Recurrent Novel ACTB-FOSB Gene Fusions

Pseudomyogenic hemangioendothelioma (PHE) is an uncommon, rarely metastasizing vascular neoplasm with predilection to affect young adults. The tumors often present as multiple nodules involving various tissue planes, including superficial and deep soft tissues as well as bone. Recurrent SERPINE1-FOSB gene fusions have been reported as the hallmark genetic abnormality in PHE, however, in our experience, a number of cases with typical histology lack this genetic abnormality. In this study, we identify a novel ACTB-FOSB gene fusion, which is as prevalent as the initial translocation reported. We selected 15 consecutive cases of PHE with typical morphologic features which had material for molecular testing. The cohort included 10 males and 5 females, ranging in age from 17 to 58 years (median age: 33 y; mean age: 35.3 y). Eight (53%) cases were located in the lower extremities (foot, calf, tibia, thigh), 5 (33%) were located in the trunk, abdomen or pelvis (abdominal wall-2, shoulder, back, ischium) and 2 (13%) were located in the upper extremity (humerus and hand). Ten (67%) cases had multifocal presentation and 5 (33%) presented as solitary lesions. Three (20%) cases were located only in the superficial dermis and subcutaneous tissues, 4 (27%) involved the superficial and deep soft tissue and 8 (53%) cases involved only the deep soft tissue and bone. Using fluorescence in situ hybridization and ARCHER fusionplex analysis we identified a novel ACTB-FOSB gene fusion in 7 cases, while the remaining 8 had the previously described SERPINE1-FOSB fusion. The clinicopathologic features and behavior of PHE associated with the ACTB-FOSB gene fusion were similar to those harboring the SERPINE1-FOSB; except that tumors with the ACTB variant were more often associated with solitary presentation. In conclusion, our results expand the spectrum of genetic alterations in PHE with a novel gene fusion identified in half of the cases. We speculate that some of the novel targeted therapies that have shown promise in SERPINE1-FOSB-positive PHE might also be beneficial in this molecular subset.

Effective Use of Sirolimus and Zoledronic Acid for Multiosteotic Pseudomyogenic Hemangioendothelioma of the Bone in a Child: Case Report and Review of Literature

Pseudomyogenic hemangioendothelioma (PMH) is a rare neoplasm with vascular and sarcomatous elements, unpredictable course, and uncommon metastatic or fatal potential. Although systemic chemotherapy has been reported with variable success, generally accepted treatment is aggressive surgery with wide margins. Evidence-based treatment options are lacking, and lack of clear prognostic features poses a risk of undertreatment or overtreatment with associated morbidity and mortality. We report the use of initial systemic therapy with oral sirolimus (SIR) and IV zoledronic acid (ZA) to induce a sustained clinical response and avoidance of amputation in a 6-year-old boy. At 37 months after diagnosis, our patient remains in sustained clinical remission as documented by x-ray, MRI, and PET-CT with return of normal mobility/activity and resolution of swelling and pain. Literature review identified 20 cases of pediatric and young adult patients with PMH, of which 7 received some form of systemic therapy. To the best of our knowledge, our patient represents the youngest reported case of PMH and the first successful and limb-sparing utilization of systemic chemotherapy as primary treatment for PMH.

Primary pseudomyogenic hemangioendothelioma of the vulva: a rare location for a rare entity

BACKGROUND

Pseudomyogenic hemangioendothelioma (PMHE) is a recently described vascular neoplasm which typically occurs in the lower extremities of young to middle-aged adults.

CASE PRESENTATION

We present here a unique case of PMHE arising primarily in the vulva of a 51-year-old woman who presented with a painful vulvar nodule. Clinically, it was thought as Bartholin gland cyst, vulvar hematoma or papilloma. On surgery, two nodules were found with one located in the superficial dermis and the other in the deep subcutis. Histologically, these two nodules showed similar features, composed of fascicles or sheets of plump spindled to epithelioid cells with eosinophilic cytoplasm. Given the morphological resemblance to a myogenic tumor, the lesion was initially diagnosed as a rhabdomyosarcoma by the referring pathologist. However, a comprehensive reevaluation of the submitted slides made us reconsider a PMHE, which was subsequently confirmed by immunohistochemical study.

CONCLUSION

This case demonstrates that PMHE can also develop in the female external genitalia albeit extremely rare. This disease should be included in the differential diagnostic list of vulvar tumors with spindled to epithelioid morphology and cytokeratin-positive immunophenotypes.

Pseudomyogenic Hemangioendothelioma

First described in 2003 as epithelioid-sarcoma-like hemangioendothelioma and later in 2011 as pseudomyogenic hemangioendothelioma, this rare vascular tumor is of intermediate malignant potential. It was officially included for the first time in the most recent World Health Organization's Classification of Tumours of Soft Tissue and Bone. It typically affects young adults with a predilection for the distal lower extremity. This tumor lacks morphologic features of vascular differentiation but shows unequivocal evidence of such differentiation with the use of relevant immunohistochemical stains such as FLI1, ERG, and CD31. Pseudomyogenic hemangioendothelioma can be diagnostically challenging and might be confused with other tumors, such as epithelioid sarcoma. In this review we discuss the clinical, morphologic, and immunohistochemical features of this tumor with particular emphasis on the differential diagnosis. Salient molecular and prognostic features are also reviewed.

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.

Sirolimus therapy in the treatment of pseudomyogenic hemangioendothelioma

Pseudomyogenic hemangioendothelioma (PMH) is a rare, mostly indolent vascular tumor. Extensive cases are treated with amputation as chemotherapy seems to be ineffective. Recently, promising results were published using mammalian target of rapamycin (mTOR) inhibitors in tumors of vascular origin. Here, we present a case of a child with advanced PMH relapsing after surgery and chemotherapy. Sirolimus achieved significant clinical improvement and stabilization of the lesions without any remarkable toxicity. This case contributes to the growing evidence regarding the efficacy of mTOR inhibitors, such as sirolimus, in multifocal PMH.

Multicentric visceral epithelioid hemangioendothelioma, with extremity dermal deposits, unusual late recurrence on the nasal bridge, and TFE3 gene rearrangement

Epithelioid hemangioendothelioma (EHE) is a malignant neoplasm with vascular differentiation that most frequently occurs within soft tissues, bone, lung, and liver. It is histologically typified by epithelioid or spindle cells present singly or in cords or clusters, many with cytoplasmic vacuoles that can contain intraluminal erythrocytes (in keeping with primitive vascular differentiation), within myxohyaline or sclerotic matrix. Up to 50% present with synchronous lesions as multifocal disease. The WWTR1-CAMTA1 fusion has been demonstrated in EHEs at a variety of sites and is considered to represent its genetic hallmark. We describe a case of EHE in a patient who initially presented with multiple liver and pulmonary deposits, was found to have a soft tissue lesion in the foot, and then presented with further lesions on the nasal bridge and the arm approximately 6 years after initial presentation. Interestingly, the case showed diffuse CAMTA1 expression but negative TFE3 immunohistochemically, but in contrast showed TFE3 gene rearrangement with fluorescence in situ hybridization but no evidence of WWTR1-CAMTA1 translocation. The clinical behavior of EHE is unpredictable, and this case highlights unusual anatomic, immunohistochemical, and molecular cytogenetic findings. Characterization of the genetics of EHE is important because targeted therapies toward products of the specific WWTR1-CAMTA1 gene fusion may have an impact in the near future.

Everolimus for Treatment of Pseudomyogenic Hemangioendothelioma

Pseudomyogenic hemangioendothelioma (PMH) is a recently described vascular neoplasm that occurs most commonly in the soft tissue of the distal extremities of young adults. Metastatic PMH can be fatal and there are no effective medications. We describe a case of a 15-year-old boy with metastatic PMH, who responded to treatment with everolimus, a mammalian target of rapamycin inhibitor. Immunohistochemistry showed that mammalian target of rapamycin was expressed in PMH biopsy specimens, which may explain the reduction in PMH tumor size following treatment.

Lower-Extremity Pseudomyogenic Hemangioendothelioma on Bone Scintigraphy and PET/CT

An otherwise healthy 33-year-old man presents with new pain involving the right leg. Radiographs of the femur showed scattered lucent lesions. An MRI of the knee demonstrated nonspecific cortical-based lesions. Biopsy confirmed pseudomyogenic hemangioendothelioma. MDP bone scan and F-FDG PET/CT were obtained to evaluate for extent of disease demonstrating disease limited to the bone of the right leg. Interestingly, the FDG and MDP uptake and CT appearance of the disease were not entirely concordant, with some lesions being lytic on CT and associated with FDG and MDP uptake, other lesions being CT silent and either MDP or FDG avid.

Differential CT and MR imaging diagnosis between low- and high-grade malignant vascular tumors of bone

Objective

To investigate the CT and MR imaging findings and differential diagnosis of malignant vascular tumors of bone.

Materials and methods

CT and MR imaging findings of 18 patients with histopathology-proven malignant vascular tumors of bone were examined. Assessed image features included age, sex, location, CT findings, and MR imaging appearances and dynamic contrast-enhanced MR imaging.

Results

The study group comprised 18 cases, of which 7 were categorized as low-grade malignant vascular tumors (LMT), and 11 were categorized as high-grade malignant vascular tumors (HMT). Malignant vascular tumors of bone showed osteolytic lesions with heterogeneous signs and enhancement, and frequently associated with soft tissue masses and peritumorous edema. The mean age of patient was respectively 34.7 years in LMT with 3 patients younger than 20 and 49.9 years in HMT with 3 patients older than 60 years. The mean lesion diameter was 3.6 cm (range 2–7.2) in LMT with two lesions <3 cm and 7.1 cm (range 3–13) in HMT with 3 lesions greater than 10 cm. LMT showed multifocal (57.1 %) and well-defined (71.5 %) lesions with residual bone (57.1 %), peripheral sclerosis (85.7 %), and slightly hetergeneous enhancement (71.4 %), compared to those of HMT with 9.1, 45.5, 27.3, and 72.7 %, and 9.1 % respectively. Also, HMT appeared as expansive (54.5 %), ill-defined (54.5 %), macroscopic necrosis/cystic (81.8 %) or hemorrhagic (27.3 %) lesion with pathological fracture (27.3 %), and often presented with obviously hetergeneous enhancement (81.8 %), compared to those of LMT with 42.9, 28.6, 42.9, 0, 14.3 and 14.3 % respectively.

Conclusions

There are some differences in the imaging features between LMT and HMT, while unifocal/multifocal, expansive, ill-defined, necrosis/cystic, hemorrhagic features with age, lesion diameter, peripheral sclerosis, residual bone tissue, pathological fracture and slightly/obviously hetergeneous enhancement highly suggest their differential diagnosis.

Epithelioid sarcoma-like hemangioendothelioma on the chest wall

Epithelioid sarcoma-like hemangioendothelioma is a rare vascular neoplasm that usually occurs in the distal extremities of young adults. Although the overall behavior of this neoplasm is usually indolent with a low risk of distant metastasis, the risk of local recurrence is significant. Therefore, initial surgical treatment with an adequate margin is important to improve the prognosis. However, epithelioid sarcoma-like hemangioendothelioma is frequently misdiagnosed. A preoperative misdiagnosis could result in resection without a sufficient margin. Herein, we describe a 68-year-old man with epithelioid sarcoma-like hemangioendothelioma on the chest wall, which was treated by wide resection despite difficulties with the preoperative diagnosis.

Epithelioid Sarcoma: Diagnostic Features and Genetics

Epithelioid sarcoma (ES) is a rare, aggressive soft-tissue neoplasm of uncertain differentiation, characterized by nodular aggregates of epithelioid cells, which are immunoreactive to cytokeratins (CKs) and epithelial membrane antigen, and often for CD34. It has a propensity for multifocal disease at presentation, local recurrence, and regional metastasis. These are aggressive neoplasms with particularly poor prognosis after regional or distant metastatic disease, for which surgical resection is still the mainstay of treatment, and options for patients with metastatic disease remain undefined. There are 2 distinct variants: classic ES, which typically presents as a subcutaneous or deep dermal mass in the distal extremities of young adults and comprises nodular distributions of relatively uniform epithelioid cells with central necrosis, and the proximal variant, which has a predilection for proximal limbs and limb girdles and the midline of the trunk, which is composed of sheets of larger, more atypical cells with variable rhabdoid morphology. Both classic and proximal-type ESs are associated with the loss of SMARCB1/INI1 protein expression, but appear otherwise molecularly relatively heterogeneous. We review classic and proximal-type ES, discussing morphology, immunohistochemical and genetic findings, the differential diagnosis, and the future potential for targeted therapies.

Cytotoxic and targeted therapy for treatment of pseudomyogenic hemangioendothelioma

Pseudomyogenic hemangioendothelioma (PMH) is a recently described, indolent vascular tumor that usually presents in the distal extremities. PMH typically has a multi-focal presentation and can involve several tissue planes including the dermis, subcutis, muscle, and bone. This soft tissue tumor predominantly affects men between 20 and 50 years of age. PMH tumors typically are resected but frequently recur locally; thus, more efficacious treatment options are needed. Herein, we report two cases of patients with PMH who were treated with systemic therapy. To the best of our knowledge, our report is the first to describe a response of PMH either to gemcitabine/taxane cytotoxic chemotherapy or to a mammalian target of rapamycin inhibitor. In the first case, a 45-year-old man with PMH of the right ilium was treated with gemcitabine plus docetaxel. Although chemotherapy was ultimately halted owing to gemcitabine-induced pulmonary toxicity, positron emission tomography-computer tomography scans taken after three cycles of gemcitabine plus docetaxel illustrated a noticeable response to the regimen. In the second case, a 22-year-old man with PMH of the right distal femur and metastases in the left ilium showed no response to gemcitabine plus docetaxel therapy, but underwent surgical resection after cisplatin and doxorubicin resulted in stable disease. DNA sequencing of his tumor revealed the presence of a tuberous sclerosis 1 (TSC1) mutation, so daily everolimus, which inhibits mammalian target of rapamycin, was started. Two months after beginning everolimus, the patient underwent magnetic resonance imaging of the pelvis, which revealed mild shrinkage of PMH metastases in the left iliac bone. Despite the apparent heterogeneity of response to gemcitabine/taxane chemotherapy in our two patients, these two cases indicate that gemcitabine/taxane and mammalian target of rapamycin inhibitor may serve as systemic treatment options for PMH and warrant further investigation.

An aggressive case of pseudomyogenic haemangioendothelioma of bone with pathological fracture and rapidly progressive pulmonary metastatic disease: case report and review of the literature

Pseudomyogenic haemangioendothelioma (PMH) is a rare recently described vascular tumour typically presenting with soft tissue disease in distal extremities of young adults. Multi-focal and multi-layered involvement is commonly recognised. The majority of cases described so far have shown an indolent clinical course and distant metastatic spread is rare. We report a case of PMH in an 82-year-old male diagnosed following a pathological fracture of the distal tibia. Further bone lesions were identified in the fibula, patella and distal femur. The patient was found to have multiple nodules suspicious for pulmonary metastases on a CT scan at the time of diagnosis that showed significant progression at a follow-up scan 4 weeks later. To our knowledge, this is the first reported case of PMH presenting with a pathological fracture. The rapid progression of bone and distant metastatic disease in this case is highly unusual given the typically indolent clinical course reported in the literature to date.

Pseudomyogenic hemangioendothelioma/epithelioid sarcoma-like hemangioendothelioma of the lower limb: report of a rare case

Pseudomyogenic hemangioendothelioma is an extremely rare soft tissue tumor, also named as epithelioid sarcoma-like hemangioendothelioma, which occurs more frequently in young adult males. It was originally recognized as a variant of epitheloid sarcoma, however it is now concluded as a distinctive, rarely metastasizing endothelial neoplasm. We present a case of pseudomyogenic hemangioendothelioma in the lower limb in a 49-year-old female who has a long course of disease and suffered from twice local recurrences and lymph node affection of the tumor. The mass was subcutaneous and the margins were ill-defined. Morphologically, the tumor cells show diversity, composed of large spindle cells and round cells, both with abundant eocinophilic cytoplasm, mimicking rhybdomyoplasts and epitheloid cells respectively. The tumor cells show diffuse strong expression of Factor VIII, Fli-1, INI-1, vimentin, MDM2, and CDK4, local expression of CD31, AE1/AE3, EMA and P63, and no expression of CD34, S-100, actin-sm, desmin, MyoD1, and HMB45. Based on these information, this case is diagnosed as pseudomyogenic hemangioendothelioma after ruling out the main differential diagnosises including epithelioid sarcoma, malignant peripheral nerve sheath tumor and rhabdomyosarcoma. From this case we suggest that pseudomyogenic hemangioendothelioma may be confused with a variety of soft tissue neoplasm histologically. The clinical feature of the case of a long course of disease with twice local recurrences and final lymph node involvement 10 years after excision of the primary tumor indicates a relative indolent behavior of this tumor.

A novel treatment for bone lesions of multifocal epithelioid sarcoma-like hemangioendothelioma

Epithelioid sarcoma-like hemangioendothelioma (ES-H) is a rare, indolent vascular neoplasm with characteristics similar to epithelioid sarcoma. It typically affects young males who present with skin and subcutaneous lesions in the extremities. Bone lesions, occurring in approximately 20% of patients, are often multifocal, seen in conjunction with soft tissue lesions, and usually found in bones of the lower extremities. This report details the case of a 20-year-old male who presented with a 1-year history of painful skin lesions on his left lower extremity. Staging studies revealed bone lesions in the cuboid and calcaneus. Bone and soft tissue pathology was consistent with ES-H. The soft tissue lesions were treated with wide excision and the bony lesions with radiofrequency ablation (RFA). The patient had no evidence of recurrence at the 2-year follow-up. Treatment of ES-H typically consists of wide excision of all soft tissue lesions and possible adjuvant radiation therapy. Management of bony lesions has included marginal excision, wide excision, amputation, chemotherapy, observation, or a combination of these modalities. ES-H has the potential for distant metastases. There is no consensus regarding the appropriate treatment of multifocal epithelioid sarcoma-like hemangioendothelioma involving bone. A potential treatment strategy of wide excision of soft tissue lesions and RFA of bone lesions is proposed.

CAMTA1 is a useful immunohistochemical marker for diagnosing epithelioid haemangioendothelioma

AIMS

The diagnosis of epithelioid haemangioendothelioma (EHE) is usually straightforward, based on characteristic histological features. However, it is sometimes difficult to differentiate EHE from a variety of other tumours with epithelioid morphology. The WW domain-containing transcription regulator 1-calmodulin-binding transcription activator 1 (WWTR1-CAMTA1) fusion gene, resulting in the overexpression of CAMTA1, is demonstrated in approximately 90% of EHEs, and the yes-associated protein 1-transcription factor E3 (YAP1-TFE3) fusion gene, associated with the strong and diffuse nuclear expression of TFE3, is present in another small subset of EHEs. The aim of our study was to examine CAMTA1 expression in EHEs and a variety of other tumours to evaluate its diagnostic utility, and to analyse TFE3 expression status in EHEs.

METHODS AND RESULTS

Immunohistochemistry was performed on 16 EHEs, including five cases with CAMTA1 rearrangement and 276 non-EHE tumours. Fourteen of 16 EHEs and only one case of ductal carcinoma of the breast were positive for CAMTA1 and its expression was focal and weak in the latter (sensitivity 87.5%, specificity 99.6%). TFE3 expression was expressed focally and weakly in three (19%) EHEs (two with the CAMTA1 rearrangement).

CONCLUSIONS

Nuclear CAMTA1 expression is sensitive and highly specific for EHE and can be applied to diagnostic immunohistochemistry in epithelioid tumours.

Contemporary diagnostics: sarcoma pathology update

Sarcoma diagnosis continues to evolve as new information is discovered. Certain tumors have been downgraded (dermal leiomyosarcoma) and an atypical category designed for others. Recently entities include myxoinflammatory fibroblastic sarcoma, myoepithelioma, and pseudomyogenic hemangioendothelioma. The terms malignant fibrous histiocytoma and hemangiopericytoma are outdated. New immunostains (STAT6, SOX10, ERG) add diagnostic specificity, and new risk assessment models are described for sarcomas where grading and staging has failed to provide adequate prognosis.

Penile pseudomyogenic hemangioendothelioma/epithelioid sarcoma-like hemangioendothelioma with a novel pattern of SERPINE1-FOSB fusion detected by RT-PCR--report of a case

We experienced a rare case of penile mesenchymal tumor in a 43-year-old Japanese man. At least three nodules were observed around the penis. The tumors were composed of spindle- to oval-shaped atypical cells with and without prominent nucleoli. These cells were like myogenic cells, but negative for myogenic markers. They were positive for endothelial markers, such as ERG, Fli1 and CD31. They were also positive for nuclear and cytoplasmic FOSB which are not expressed in epithelioid hemangioendothelioma or epithelioid sarcoma. These pathological and immunohistochemical findings strongly suggested pseudomyogenic hemangioendothelioma/epithelioid sarcoma-like hemangioendothelioma (PHE/ES-HE). Since a recent report directly proved that two cases of PHE/ES-HE have SERPINE1-FOSB fusion gene by reverse transcription-polymerase chain reaction (RT-PCR), we examined whether the fusion gene is present or not in the present case by RT-PCR using fresh frozen surgical material. Sequencing of the PCR product revealed that this case has SERPINE1-FOSB fusion. The fusion pattern of our case was different from those of two previously reported cases. In our case, 86 nucleotides of SERPINE1 intron 1 were inserted between SERPINE1 exon 1 and the middle portion of FOSB exon 1, and a putative translation start codon was identified in SERPINE1 intron 1. Thus, this is the third case of PHE/ES-HE with SERPINE1-FOSB fusion proved by RT-PCR.