Superficial primitive neuroectodermal tumor/Ewing sarcoma (PN/ES): same tumor as deep PN/ES or new entity?

Myxofibrosarcoma in adolescents and young adults: a clinicopathologic study of 17 cases

Myxofibrosarcoma is a locally aggressive sarcoma that characteristically arises in the extremities of older patients. Cases arising at a younger age are rare, leading to diagnostic challenges. Our aim was to study the clinicopathologic features of myxofibrosarcoma in patients aged ≤40 years. Cases of myxofibrosarcoma and myxoid malignant fibrous histiocytoma arising in patients aged ≤40 years with clinical follow-up were collected from multiple institutions. Hematoxylin and eosin slides were evaluated for mitoses, necrosis, and epithelioid areas. Seventeen cases were identified (13 females, 4 males; 16-39 years; median 32 years), tumors ranged from 2.2 to 34 cm (median 4.1 cm). Anatomic sites included proximal extremity (9), distal extremity (4), trunk (1), and head/neck (3). Ten were superficial, and 6 were deep-seated. Three cases were predominantly epithelioid. In untreated resection specimens, 6 were FNCLCC grade 1, 4 grade 2, and 2 grade 3. Follow-up (6-204 months, median 36 months) revealed that 2 patients experienced local recurrences, 1 distant metastasis, and 2 patients both. The 5-year overall survival (OS) and event-free survival (EFS) were 84% and 55.9%, respectively. Tumor depth and necrosis were correlated with inferior OS (P = .025, P = .005), while tumor depth was also associated with worse EFS (P = <.001). We conclude that myxofibrosarcomas arising in adolescents and young adults show similar behavior compared to their older adult counterparts. Tumor depth and necrosis are poor prognostic factors in myxofibrosarcoma in this age group. Awareness that myxofibrosarcoma can rarely present in this population is important for accurate diagnosis.

Bone and soft tissue tumors: clinicoradiologic-pathologic molecular-genetic correlation of novel fusion spindled, targetable-ovoid, giant-cell-rich, and round cell sarcomas

BACKGROUND

New entities in the classification of bone and soft tissue tumors have been identified by use of advanced molecular-genetic techniques, including next-generation sequencing. Clinicoradiologic and pathologic correlation supports diagnostic classification.

METHODS

Tumors from four morphologically grouped areas are selected to enhance diagnosis and awareness among the multidisciplinary team. These include select round cell tumors, spindle cell tumors, targetable tyrosine kinase/RAS::MAPK pathway-ovoid (epithelioid to spindled) tumors, and giant-cell-rich tumors of bone and soft tissue.

RESULTS

Round cell tumors of bone and soft tissue include prototypical Ewing sarcoma, newer sarcomas with BCOR genetic alteration and CIC-rearranged, as well as updates on FUS/EWSR1::NFATc2, an EWSR1 non-ETS tumor that is solid with additional amplified hybridization signal pattern of EWSR1. This FUS/EWSR1::NFATc2 fusion has now been observed in seemingly benign to low-grade intraosseous vascular-rich and simple (unicameral) bone cyst tumors. Select spindle cell tumors of bone and soft tissue include rhabdomyosarcoma with FUS/EWSR1::TFCP2, an intraosseous high-grade spindle cell tumor without matrix. Targetable tyrosine-kinase or RAS::MAPK pathway-tumors of bone and soft tissue include NTRK, ALK, BRAF, RAF1, RET, FGFR1, ABL1, EGFR, PDGFB, and MET with variable ovoid myopericytic to spindled pleomorphic features and reproducible clinicopathologic and radiologic clues to their diagnosis. Giant-cell-rich tumors of bone, joint, and soft tissue are now respectively characterized by H3F3A mutation, CSF1 rearrangement (targetable), and HMGA2::NCOR2 fusion.

CONCLUSION

This article is an update for radiologists, oncologists, surgeons, and pathologists to recognize these novel ovoid, spindled, giant-cell-rich, and round cell tumors, for optimal diagnostic classification and multidisciplinary team patient care.

Congenital Cutaneous Peripheral Primitive Neuroectodermal Tumor (pPNET) of Scalp: Youngest Case So Far

Congenital cutaneous peripheral primitive neuroectodermal tumor (pPNET) is very rare and also very rarely located in scalp. Only two cases of PNET as primary tumor in scalp are reported so far in the literature. Non mutilating surgical excision, combined with chemotherapy and radiotherapy are used in treating these rare tumors. We present the youngest case report of PNET of scalp in 10-month-old girl who was managed by surgical excision with good cosmetic outcome and disease-free 20 months post-operative period.

Ewing's Sarcoma/Peripheral Primitive Neuroectodermal Tumors in Bronchus

Ewing sarcoma/peripheral primitive neuroectodermal tumors (ES/pPNET), a member of the Ewing sarcoma family of tumors, is a malignant soft tissue tumor with small undifferentiated neuroectodermal cells. Primary trachea-bronchial ES/pPNET is very rare. The most common pulmonary ES is due to a metastasis. We describe a case of ES/pPNET which originated in the left basal trunk bronchus. The patient was a 30-year-old male, presenting with irritable cough and fever for 10 days. A tumor of 60 mm in diameter was found in the left basal trunk bronchus, extending to the left lower lobe. No distant metastases were detected. Histopathological examination revealed a malignancy of ES/pPNET with a diffuse proliferation of round cells, a Flexner-Wintersteiner rosette formation and positive staining for CD99. The patient was successfully treated with a combination of left lower lobectomy and adjuvant chemotherapy and has remained disease-free for approximately 18 months at follow-up. This case highlights that ES/pPNET should be considered as a differential diagnosis in cases of trachea-bronchial tumors.

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

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

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

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We treated this tumor with surgery alone.

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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.

Primary subcutaneous spindle cell Ewing sarcoma with strong S100 expression and EWSR1-FLI1 fusion: a case report

Ewing sarcoma is described classically as a small, round cell tumor of bone and soft tissue in children and young adults. Ewing sarcoma most often is characterized by a fusion of the Ewing sarcoma breakpoint region 1 (EWSR1) and the Friend leukemia virus integration 1 (FLI1) genes, forming an EWSR1-FLI1 fusion transcript. We report an exceptional case of primary subcutaneous Ewing sarcoma in a 16-year-old female composed entirely of spindle cells with focal fascicular growth and exhibiting strong, diffuse immunohistochemical reactivity for S100, unlike classic Ewing sarcoma. However, reverse transcription-polymerase chain reaction (RT-PCR) analysis confirmed the presence of a rare variant of the EWSR1-FLI1 fusion transcript, featuring fusion of EWSR1 exon 10 to FLI1 exon 6. To our knowledge, the combined histologic, molecular, and clinical features have not been reported previously in Ewing sarcoma, and raise a broad differential diagnosis emphasizing the importance of molecular techniques in the diagnosis of this tumor.

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.

Ewing sarcoma/peripheral primitive neuroectodermal tumor and related tumors

Ewing sarcoma/peripheral primitive neuroectodermal tumor (EWS/pPNET) and other tumors with EWS gene rearrangements encompass a malignant and intermediate neoplasm with a broad anatomic distribution and a wide age range but a predilection for soft tissue in children, adolescents, and young adults. The overlapping histologic, immunohistochemical and cytogenetic and molecular genetic features create diagnostic challenges despite significant clinical and prognostic differences. Ewing sarcoma is the 3rd most common sarcoma in children and adolescents, and desmoplastic small round cell tumor is a rare neoplasm that occurs more often in older children, adolescents, and young adults. Pathologic examination is complemented by immunohistochemistry, cytogenetics, and molecular genetics. This article reviews the clinicopathologic features of EWS/pPNET and desmoplastic small round cell tumor in the spectrum of tumors with EWS gene rearrangements. Other tumors with different histopathologic features and an EWS gene rearrangement are discussed elsewhere in this volume.

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.

Primary vulvar Ewing sarcoma/primitive neuroectodermal tumor: a report of 2 cases and review of the literature

Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET) family of tumor is a very aggressive malignant round cell tumor characterized by translocations involving EWS-FLI1 genes. They are increasingly recognized in extraosseous sites as a result of improvements in diagnostic tools. In this paper, we report 2 additional cases arising in vulva of young adults who have been treated aggressively and have survived fore more than 7 and 4 years successively. Histologic examination showed small round (blue) cell morphology in both cases. The tumor cells contained glycogen and were positive for CD99 and vimentin and negative for keratins, lymphoid markers, S-100, synaptophysin, chromogranin, and desmin. Reverse transcriptase polymerase chain reaction analysis from paraffin-embedded tissue revealed EWS-FLI1 fusion product in 1 case. Collectively, 13 cases of vulvar ES/PNET have been reported in the literature. Only 8 cases have detailed follow-up information with an average follow-up data of 28 months. Ewing sarcoma/PNET should be considered in the differential diagnosis of any undifferentiated tumors involving the lower gynecologic tract and all axillary tests including molecular tests should be performed for correct diagnosis because prolonged survival is possible for this dreadful disease after complete surgical resection, followed by adjuvant therapy.

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

Aims:

To perform a clinicopathological analysis of a series of primary cutaneous Ewing sarcomas/primitive neuroectodermal tumours (ES/PNET) to highlight the pathological features, discuss the differential diagnosis, emphasise the role of molecular testing (particularly fluorescence in situ hybridisation, FISH) in diagnosis and outline the patients’ clinical course.

Methods:

Seven cases of primary cutaneous ES/PNET were identified from the authors’ consultation files.

Results:

The patients were aged 16–61 years (median 25). Five were female and two were male. Five cases involved the limbs and two the trunk. Five were initially misdiagnosed (three as carcinoma and two as melanoma). All cases were characterised histologically by sheet-like growth of small round cells with little cytoplasm and showed strong membranous staining for CD99 and positive but variable staining for FLI-1. Six patients showed an EWS rearrangement (five on FISH analysis and one on RT-PCR). All tumours were completely excised. Three patients received adjuvant chemotherapy, one of whom also received radiotherapy. Follow-up was available in all cases (range 11–57 months; median 41). No recurrences or metastases occurred.

Conclusions:

Although rare, primary cutaneous ES/PNET should be considered in the differential diagnosis of cutaneous “small blue cell tumours”. Immunostaining for FLI-1 and molecular testing for evidence of an EWS rearrangement are useful ancillary investigations to confirm the diagnosis. The prognosis of primary cutaneous ES/PNET appears to be more favourable than extracutaneous ES/PNET.

Merkel cell carcinoma: review

Merkel cell carcinoma (MCC) is synonymous with primary cutaneous neuroendocrine carcinoma. It tends to affects elderly whites, but there is also an increased incidence among immunosuppressed patients. The recent identification of a novel polyomavirus associated with the tumor has stimulated renewed interest in its pathogenesis. MCC tends to show classic histologic features of a neuroendocrine carcinoma and is often positive for CK20, but nonclassic cytologic findings and unusual immunophenotypes may be observed and can lead to a diagnostic confusion. MCC needs to be distinguished from other primary cutaneous tumors with a small cell appearance and metastatic tumors. Surgical excision is the treatment of choice, but radiation therapy has also found to be effective. Sentinel lymph node biopsy has become an integral part of the staging of patients with MCC.

Superficial primitive Ewing's sarcoma: a clinicopathologic and molecular cytogenetic analysis of 14 cases

Superficial primitive Ewing's sarcomas are rare and have been reported to be of favorable prognosis compared to conventional deep-seated tumors. In the skin and subcutis, the diagnosis is often difficult, and performing molecular cytogenetic techniques may be helpful. We performed a retrospective analysis of 14 cases of superficial Ewing's sarcomas, all confirmed by molecular cytogenetics. Clinical, histological, immunohistochemical, molecular cytogenetic, therapeutic, and follow-up data are reported. There were 11 female and 3 male patients aged from 12 to 77 years (median: 17 years). Seven tumors occurred in the extremities, five in the trunk wall, and two in the head. Tumor size ranged from 1 to 5 cm (median, 3 cm). They were all small round-cell proliferations with a strong membranous positivity for CD99. Ewing's sarcoma translocations/fusion gene transcripts were detected in eight cases, both by FISH and reverse transcriptase (RT)-PCR. Four tumors were positive by RT-PCR alone (FISH not done in three cases and not interpretable in one case), and two cases were positive by FISH alone (RT-PCR not done). Surgical resection was performed in all patients. Chemotherapy was given in ten patients and radiotherapy in six. At last medical examination (median follow-up, 47 months), two patients who underwent surgical resection alone had died from the tumor. Our results confirm that superficial Ewing's sarcomas are of good prognosis. Given the difficulty of the diagnosis and the importance of an adapted treatment, a confirmation of the diagnosis by molecular or cytogenetic techniques is recommended when dealing with a superficial tumor.