Primary cutaneous Ewing sarcoma/primitive neuroectodermal tumour: a clinicopathological analysis of seven cases highlighting diagnostic pitfalls and the role of FISH testing in diagnosis

Updates on WHO classification for small round cell tumors: Ewing sarcoma vs. everything else

The WHO Classification of Soft Tissue and Bone Tumours currently recognizes four categories of undifferentiated small round cell sarcoma: Ewing sarcoma, round cell sarcoma with EWSR1-non-ETS fusions including NFATc2 and PATZ1, CIC-rearranged sarcoma, and sarcoma with BCOR genetic alterations. These neoplasms frequently pose significant diagnostic challenges due to rarity and overlapping morphologic and immunohistochemical findings. Further, molecular testing, with accompanying pitfalls, may be needed to establish a definitive diagnosis. This review summarizes the clinical, histologic, immunohistochemical, and molecular features of these neoplasms. In addition, differential diagnosis and areas of uncertainty and ongoing investigation are discussed.

Primary cutaneous Ewing sarcoma in a young boy

We report a 10-year-old boy with the challenging presentation of a left toe nodule that failed empiric treatments and was biopsied. Immunohistochemistry and florescence in situ hybridization enabled the diagnosis of Ewing sarcoma (ES). This case emphasizes the importance of including ES on the clinical differential to minimize diagnostic delays.

Primary cutaneous Ewing sarcoma with diffuse S100/SOX10 positivity and pseudoalveolar pattern: An extraordinarily rare case highlighting a potential pitfall with significant repercussions

Primary cutaneous Ewing sarcoma is a very rare entity with less than 100 cases reported in the literature, sharing the same morphological and immunohistochemical characteristics as their osseous counterparts. Herein, to the best of our knowledge, we report the first case in English literature of a molecularly confirmed Ewing sarcoma with diffuse and strong SOX10 immunoreactivity. This exceedingly rare immunohistochemical finding along with the rarity of this tumor could easily lead to a misdiagnosis with significant repercussions. Our case highlights the difficulty in diagnosing primary cutaneous Ewing sarcoma as well as the pivotal role molecular diagnostics can play in specific scenarios.

Ewing-Like Sarcoma: A Case of a Primary Cutaneous Primitive Neuroectodermal Tumor With Atypical Immunohistochemistry and Lack of Fusion Oncogene Detection

We present a 25-year-old male patient with a primary cutaneous primitive neuroectodermal tumor (cPNET) with unusual immunohistochemistry and lack of fusion oncogene generation. The lesion expressed CD99 and WT-1, and the histological features were consistent with cPNET. Differential diagnoses such as rhabdomyosarcoma, desmoplastic small round blue cell tumor, hematolymphoid neoplasm, neuroblastoma, and CIC-DUX round cell sarcoma were ruled out based on immunohistochemistry, genetic studies, and histology. Previous cPNET cases have been published detailing abnormal immunochemistry and genetic expression. However, to our knowledge, fusion oncogene negativity in cPNET tumors has only been reported in one other published case series. These reports, including this study, reinforce the fact that a high index of suspicion should be used when diagnosing these tumors, regardless of immunohistochemical and genetic variability. This case highlights that the typical genetic and immunohistochemical features of cPNET may be more variable than previously thought. Future studies are needed to better understand these variations of cPNET.

Primary cutaneous Ewing sarcoma presenting as a chest wall lesion

A 10-year-old boy presents with a rare case of primary cutaneous Ewing sarcoma. The left-sided chest wall lesion was initially thought to be a benign haemangioma and treated with cryotherapy. Within 4 months, the lesion returned and post excision was found to be primary cutaneous Ewing sarcoma on histology. Few cases of primary cutaneous Ewing sarcoma exist in the literature, and although it is a rare differential for paediatric skin lesions, it is an important consideration due to the associated mortality risk in this young cohort.

Selected Diagnostically Challenging Pediatric Soft Tissue Tumors

Many benign and malignant soft tissue tumors in children are challenging and their diagnosis requires knowledge of their vast diversity, histopathological complexity, and immunohistochemical, cytogenetic, and molecular characteristics. The importance of clinical and imaging features cannot be overstated. Soft tissue sarcomas account for 15% of all pediatric malignancies after leukemia/lymphoma, central nervous system tumors, neuroblastoma and Wilms tumor. This article discusses selected challenging pediatric soft tissue tumors with an update on recently described entities.

A peculiar case of large primary cutaneous Ewing's sarcoma of the foot: Case report and review of the literature

•

Primary cutaneous Ewing sarcoma of the foot are rare and usually small tumors.

•

The present case is the largest primary cutaneous Ewing sarcoma of the foot.

•

We treated this tumor with surgery alone.

•

These tumors should be considered into differential diagnosis of superficial lesions.

Introduction

Primary cutaneous extraskeletal Ewing’s sarcomas (ESs) are extremely rare tumors, limited to the skin and generally appear as a single small lesion, circumscribed mid-to-deep dermis or involving subcutis. Due to their rarity and morphological similarity to other cutaneous tumors, ESs are subject to being clinically and pathologically subdiagnosed.

Presentation of case

A 37-year-old man presented a large rapidly growing mass of the first toe measuring 9.5 × 8 cm with no radiological evidence of bone involvement. The patient underwent wide surgical tumor resection; histological, immunohistochemical and molecular evaluation confirmed the diagnosis of ESs. Postoperative examinations revealed no metastasis and after 11 months follow-up no recurrences were detected.

Discussion

Current literature reports only a few isolated cases or small series. ESs are generally described as small masses with a favorable clinical behavior. Despite lower extremity is a relatively frequent site, only rare and small ESs of the foot have been reported. To our knowledge the present case is the largest ES of the foot. Despite its large size, the patient did not report any metastases confirming the hypothesis of treating superficial ES with surgery alone, thus avoiding adjuvant radiotherapy and/or chemotherapy and their related side-effects.

Conclusion

ESs still remain exceedingly rare tumors and they could not be taken in consideration into differential diagnosis. This case represents a peculiar example of large ES in an uncommon site as the foot successfully treated with surgery alone, and may serve as an alert for those physicians who approach such rapidly growing superficial lesions.

Primary Cutaneous Ewing Sarcoma: Report of a Case

Primary cutaneous Ewing's sarcoma is a rare entity. Although the diagnosis may be very difficult, it can be confirmed through molecular biology. We present the case of a 13-years old male with a lesion in the sole of the right foot, characterized by a monomorphous proliferation of small, round and blue cells. The histology and molecular biology allowed us to perform the diagnosis of cutaneous Ewing's sarcoma. This neoplasm must be distinguished from other round cell tumors with cutaneous involvement. The prognosis and treatment of this rare disease will also be discussed.

Primary cutaneous Ewing sarcoma--case report

Ewing sarcoma is a primitive neuroectodermal tumor rarely occurs in the skin and sobcutaneous tissues. Generally Ewing's sarcoma is a primary bone tumor, but when present in soft tissues it characterizes an extremely uncommon clinical picture. It usually involves the deep subcutaneous tissue or muscles, and more rarely occurs like a primary skin cancer. Most patients are white, women, and in the second decade of life. The clinical features are a superficial mass, in average measuring 2-3 cm, of soft consistency, freely mobile and sometimes painful. The more affected locations are upper and lower extremities, trunk, head, neck or multiple lesions. The presence of metastases is very rare.

Cutaneous neoplasms showing EWSR1 rearrangement

Rearrangements of the EWSR1 gene are found in an increasing number of human neoplasms, including several tumors that can involve the skin: Ewing sarcoma/primitive neuroectodermal tumor, angiomatoid (malignant) fibrous histiocytoma, myoepithelioma of soft tissue, and clear cell sarcoma. Although these tumors share this common genetic link, they have very different clinical features, morphology, immunophenotype, and sometimes fusion gene partners; these will be the subjects of this review.

Primary cutaneous Ewing sarcoma: a systematic review focused on treatment and outcome

BACKGROUND

Despite intensive treatment, the overall prognosis of Ewing sarcoma of the bone remains poor. Primary cutaneous Ewing sarcoma very rarely occurs and the prognosis has been reported to be better in some small series. All cases of Ewing sarcoma are currently treated in the same way, regardless of their location.

OBJECTIVES

To determine whether Ewing sarcoma of the bone and primary cutaneous Ewing sarcoma are different in terms of epidemiology and prognosis.

METHODS

A systematic review of the literature was carried out using the keywords 'cutaneous Ewing's sarcoma', 'primary Ewing's sarcoma of skin' and 'primary neuroectodermal tumour and skin' in the Medline database. Series of five or more cases were included.

RESULTS

Six series met the inclusion criteria, making a total of 61 patients. Median age at diagnosis was 17 years and 33% were male. The median size of the tumour was 2·3 cm. The treatment consisted of surgery in all cases, adjuvant multiagent chemotherapy in 69% of cases, adjuvant chemoradiotherapy in 38% of cases and adjuvant radiotherapy without adjuvant chemotherapy in 3% of cases. Six patients developed metastases, four of whom died. The overall survival was 93% and the 10-year probability of survival was estimated at 91% (95% confidence interval 83-100).

CONCLUSION

This systematic review demonstrated epidemiological and prognostic differences between Ewing sarcoma of the bone and primary cutaneous Ewing sarcoma. Primary cutaneous Ewing sarcoma has a female predominance, occurs at a later age, but, more importantly, has a better outcome. Multimodal therapy for Ewing sarcoma is associated with immediate and long-term morbidity and mortality. Although the size of our study does not allow a definitive conclusion about treatment modalities, we suggest that a less toxic approach compared with conventional treatment should be investigated in primary cutaneous Ewing sarcoma.

Cutaneous Ewing sarcoma: report of 2 cases and literature review of presentation, treatment, and outcome of 76 other reported cases

Cutaneous Ewing sarcoma is a rare variant that has been poorly characterized and has no standard therapy. We report 2 patients with cutaneous Ewing sarcoma and review 76 other cases reported in the literature for demographics, presentation, treatment, and outcome. Only 2 patients presented with metastatic disease, and only 8 patients developed metastatic disease. Ninety-one percent of all patients are alive despite wide variations in treatment regimens. On the basis of this summary, treatment consisting of local control with surgery and/or radiation and abbreviated chemotherapy is proposed as a treatment option for this less aggressive Ewing sarcoma.

Primary cutaneous Ewing's sarcoma/primitive neuroectodermal tumor manifesting numerous small and huge ulcerated masses: its complete remission by chemotherapy and magnetic resonance imaging findings

Extraskeletal Ewing's sarcoma (ES) and primitive neuroectodermal tumor (PNET) are widely regarded as clinically and histologically identical tumors which consist of small blue round cells. Extraskeletal ESs/PNETs usually occur in the deep soft tissues of the paraspinal region, chest wall, or lower extremities. However, superficially located cases, so-called cutaneous ESs/PNETs, are exceedingly rare, and the vast majority of the reported cases present as a single small mass. We present magnetic resonance imaging (MRI) findings and clinical course of a unique case of primary cutaneous ES/PNET presenting as numerous huge masses with severe ulceration on them.

Primary Subcutaneous Ewing Sarcoma Presented as Pseudo Aneurysmal Subcutaneous Tumor

BACKGROUND

Extraskeletal Ewing's sarcoma is a rare malignant tumor of mesenchymal origin, which is histologically similar to primary osseous Ewing's sarcoma. It has been well described in deep soft tissues. However, location in cutaneous or subcutaneous tissue has rarely been reported. Being seen principally in children, it can be seen, rarely, in old men.

CASE REPORT

We present a case of subcutaneous Ewing sarcoma within the left shoulder of a 49-year-old man, without osseous involvement. Physical examination suggested a vascular tumor. Histologically, it was a small round cell tumor that marked strongly for CD99. The diagnosis of subcutaneous Ewing sarcoma was performed.

CONCLUSION

Ewing sarcoma is a rare malignant small round cell tumor of the skin and subcutaneous tissue. It should be differentiated from other cutaneous neoplasms composed of small round cells.