An unusual case of primary cutaneous Ewing sarcoma in an adult

Primary cutaneous/subcutaneous Ewings sarcoma

Amongst Ewing sarcoma family of tumours, (EFST), cutaneous/subcutaneous Ewing sarcoma are defined as tumours arising from cutaneous or subcutaneous tissue, not invading the underlying aponeurosis. They are rare tumours, with less than 200 patients published. They are typically small tumours (less than 5cm), and can arise at any anatomical location, with a particular tropism for distal, truncal and head/neck locations, compared to classical Ewing sarcoma. Like other conjunctive tumours, they have to be treated in specialized centers, with a diagnostic procedure following ESMO guidelines about soft-tissue tumours, favoring a core needle biopsy in most cases. They share classical pathological and molecular features of EFST (including EWSR1 rearrangement). Metastatic presentation is rare (less than 5% at diagnosis), but must be carefully searched using appropriated imaging considered the bad prognosis of these patients. Treatment strategy relies on neoadjuvant and adjuvant chemotherapy, surrounding the local treatment. Patients with localized disease have good prognosis and have to be treated with the dual objective of curability, and of minimizing acute and late toxicity. That is why in case of small tumours (<200mL), patients can be treated with less intensive protocols, as Saint Jude's (low-dose semi-continuous cyclophosphamide/doxorubicin regimen as induction chemotherapy and vincristine/actinomycin courses as maintenance therapy), setting aside the option of classical VDC/IE protocol for larger tumors. Local treatment must rely on carcinologic surgery, with the aim to avoid radiotherapy when possible. Patients with metastatic disease have bad prognosis resemble classical Ewing sarcoma, and have to be treated accordingly.

A large femoral primary cutaneous Ewing's sarcoma in a 35-year-old woman: Case report

INTRODUCTION

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 PRESENTATION

We present a case of large primary cutaneous Ewing sarcoma within the left thigh of a 35-year-old woman, without osseous involvement. Physical examination. Histologically, it was a small round cell tumor that marked strongly for CD99. The diagnosis of cutaneous Ewing sarcoma was performed.

DISCUSSION

The things that distinguish our case are that it is the first case in Syria, in addition to the size of the large tumor with diameters of 15 × 20 cm, and it is in a 35-year-old woman.

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.

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.