Primitive neuroectodermal tumor of the kidney--another enigma: a pathologic, immunohistochemical, and molecular diagnostic study

Renal primitive neuroectodermal tumor. The first case series from Syria

Primitive neuroectodermal tumor (PNET) mainly arises from soft tissues of the extremities such as humerus, femur, C tibia. It rarely arises from kidney; less than 200 cases have been reported in the literature. The clinical presentation and radiography findings are not specific. Here we first report two cases of renal primitive neuroectodermal tumor in Syria.

the first patient was 26-year-old- female that presented to urology clinic complaining of right flank pain. Ultrasonography of the abdomen showed a large mixed heterogeneous mass in the right kidney with no hemorrhage or calcification and MSCT of abdomen and pelvis demonstrate a mixed well-demarcated heterogeneous mass measuring (74*117) mm in the right kidney right radical nephrectomy was performed.

The second patient 19-year-old-male presented with left flank pain. Ultrasonography of the abdomen showed mixed large mass involving the left kidney, with unmarked border. The CT of the abdomen and pelvis demonstrating a (30*110*90) mm left renal mass and periaortic lymphadenopathy measuring (45*28) mm. The patient underwent Left radical nephrectomy with periaortic lymphadenectomy dissection. The final diagnosis for both cases was Renal PNET based on microscopic and immunohistochemistry examination.

In patient with suspected renal mass in the radiographic images, the diagnosis of renal primitive neuroectodermal tumor should be kept in the mind despite its rarity. The final diagnosis is done by histopathological study in association with immunohistochemical examination.

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Here we will first report two cases of renal PNET in Syria.

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The diagnosis of renal primitive neuroectodermal tumor should be kept in the mind despite its rarity.

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The final diagnosis is done by histopathological study in association with immunohistochemical examination.

Imaging Findings of Hepatic Ewing's Sarcoma on Computed Tomography and Gadobenate Dimeglumine-enhanced Magnetic Resonance Imaging: A Case Report and Literature Review

Ewing's sarcoma (ES) is a tumor that often occurs in the long bones and rarely arises from visceral organs primarily. Here, we report a case of primary hepatic ES, discuss its computed tomography (CT) and gadobenate dimeglumine-enhanced magnetic resonance (MRI) features. This is the first Chinese and fifth primary hepatic ES case reported, based on a literature review. Imaging examinations showed that the tumor was solid, with necrosis and hemorrhage. Contrast-enhanced images showed that the tumor was hypervascular and especially had heterogeneous signal intensity on hepatobiliary phase MRI images. Intratumoral vessels and vascular invasion were also present.

Do Primitive Neuroectodermal Tumors of the Kidney Have a Predilection for Inferior Vena Cava Involvement? A Case Series and Review of the Literature

The primitive neuroectodermal tumor (PNET) of the kidney is an extremely rare neoplasm, the diagnosis of which mainly depends upon histopathology, immunohistochemistry (IHC), and cytogenetics. A handful of cases reported in the literature mention about aggressive features of this neoplasm. The purpose of our study was to review our experience in not only the diagnosis and management of the patients with renal PNET but also to highlight its propensity to involve inferior vena cava (IVC) and also present a rare occurrence of Ewing's sarcoma (ES)/PNET of the renal pelvis. The clinical, operative, and histopathology records of four patients of renal PNET treated between January 2017 and December 2019 were reviewed and data analyzed concerning the available literature. Out of the four patients treated, two had level III and IV IVC thrombus, and one had dense desmoplastic adhesions with the IVC wall. One of the cases had a rare presentation of ES/PNET of the renal pelvis. All patients were managed surgically, while only one patient received adjuvant chemotherapy and following up with remission for the last 2 years and 4 months. On IHC, cluster of differentiation-99 (CD-99) was positive in all patients, and three were positive for Friend leukemia integration-1. PNET of the kidney is primarily an immunohistopathological diagnosis. This neoplasm has an increased propensity for the local invasion of surrounding structures. A multimodality approach with surgery, chemotherapy, and radiotherapy could offer better outcomes, although the prognosis of these tumors remains poor.

Primary pancreatic Ewing sarcoma: a cytomorphologic and histopathologic study of 13 cases

INTRODUCTION

Ewing sarcoma (ES) is a small, round cell sarcoma that rarely occurs in solid organs, including the pancreas. A diagnostic overlap exists with other primary pancreatic neoplasms, especially for specimens from small biopsies and fine needle aspiration (FNA). To improve the diagnosis of this rare pancreatic tumor, we have reported a series of 13 cases of primary pancreatic ES and reviewed the cytopathologic, surgical pathology, clinical, and radiologic features of these neoplasms.

MATERIALS AND METHODS

We performed a retrospective case review of 13 patients with a diagnosis of pancreatic ES from 2 tertiary academic medical centers. A combination of cytology and histopathologic slides were reviewed, and the patient demographics, clinical information, somatic genetics, and radiologic findings were obtained from the electronic medical records.

RESULTS

Five FNA specimens from 5 patients and 8 surgical biopsy or resection specimens were identified and reviewed. The patients included 9 males and 4 females, with a median age of 27 years (range, 15-78 years). The cytology smears were highly cellular and showed a combination of complex tissue fragments and singly dispersed small round blue cells. The final diagnosis was ES for all 5 FNA specimens in accordance with the characteristic cytomorphology, diffuse and/or strong membranous immunolabeling for CD99, membranous β-catenin, and molecular confirmation of EWSR1 using fluorescence in situ hybridization or reverse transcriptase polymerase chain reaction.

CONCLUSIONS

The cytologic diagnosis of ES is challenging, especially in unusual locations such as the pancreas. However, the correct cytologic diagnosis is important because these patients will require neoadjuvant therapy before surgery. Confirmatory molecular studies should be required to render the diagnosis of pancreatic ES.

Primary renal Ewing's sarcoma in a young male treated completely by surgical excision without chemotherapeutic agents: Case report

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Primary renal Ewing sarcoma is a rare tumor in adults.

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Proper surgical resection is the most important treatment step.

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Further studies needed to establish treatment for this tumor.

Introduction

Primary renal Ewing’s sarcoma is a rare tumor with dismal prognosis. The main treatment modality of treatment is surgical excision with adjuvant or neoadjuvant chemotherapy.

Case presentation

We present a case of primary renal EWS in 27-year-old male. He presented to our center complaining of three days history of severe left flank pain associated with nausea and vomiting. Computerized tomography (CT) revealed a 10 × 7 × 6.5 cm left lower pole renal mass. Left radical nephrectomy was performed and revealed a tumor with uniform round to oval nuclei cells. The cells stained strongly positive for CD 99. The diagnosis was established as primary renal Ewing’s sarcoma. The patient refused the chemotherapy. Fortunately, he was free of the disease on regular clinical and radiological follow-up, the last follow up was 30 months post-nephrectomy.

Conclusion

This case highlights the importance of proper surgical treatment and its role in the managing this type of malignancy especially in localized disease at presentation.

Primitive neuroectodermal tumor of kidney with Level III inferior vena cava thrombus

Primitive neuroectodermal tumor (PNET) of the kidney is an extremely rare renal neoplasm with only about 50 reported cases in the literature. These tumors behave aggressively and carry a poor prognosis. A 22 years female patient presented with right lumber and right hypochondrium lump of 4 months duration. Commutated tomography revealed large right renal mass with renal vein and inferior vena cava (IVC) thrombus. Magnetic resonance imaging abdomen demonstrated the extension of tumor thrombus up to the junction of hepatic vein and IVC. Preoperative percutaneous needle biopsy was performed. Histopathology demonstrated small round to oval cells with scanty cytoplasm and cells are arranged in clusters. Immunohistochemical staining demonstrated a highly specific cluster of differentiation 99, confirming the diagnosis of a PNET.

Primitive neuroectodermal tumour of kidney with thrombosis of the inferior vena cava and good responsive to surgical and medical treatment: description of a case and revision of literature

Primitive neuroectodermal tumour (PNET) of kidney is a rare cancer typical of young adults with few cases described in the literature. We report a case of renal PNET in a 31-year-old man who presented to our department with a computed tomographic (CT)-scan revealing a large renal mass of 20 cm, massive thrombosis of the inferior vena cava (IVC). The patient underwent radical nephrectomy with contextual retroperitoneal lymphadenectomy and resection of IVC needing Dacron prosthesis substitution. Definitive histopathological examination showed PNET of kidney infiltrating ipsilateral adrenal gland, massive cava thrombosis with infiltration of vena cava wall and one lymph nodal metastasis. Postoperative PET-scan showed metastatic lesions in bilateral adrenal glands and pancreas. The patient received chemotherapy, and currently, he is in follow-up after 26 months from first diagnosis without any sign of recurrence of disease. Kidney PNET usually is associated with poor prognosis, so, it needs an early identification and differentiation from other similar small cells tumours in order to obtain a good response to the treatments.

Pediatric renal and genitourinary tract tumors and the contributions of Dr. Louis "Pepper" Dehner therewith

Dr. Louis "Pepper" Dehner is an internationally renowned surgical pathologist, especially in the subspecialty of pediatric pathology. Although his clinical and academic expertise are broad, with over 400 published articles, some of his most intriguing contributions have been in the area of pediatric renal and genitourinary pathology. This review focuses on the entities in these following organ systems where he has focused his efforts: malignant rhabdoid tumor, renal medullary carcinoma, Ewing sarcoma/peripheral neuroectodermal tumor, and the DICER1-related lesions cystic nephroma, embryonal rhabdomyosarcoma of the uterine cervix, and Sertoli-Leydig cell tumor.

Pediatric soft tissue tumor pathology: A happy morpho-molecular union

Since its foundation by remarkably talented and insightful individuals, prominently including Pepper Dehner, pediatric soft tissue tumor pathology has developed at an immense rate. The morphologic classification of tumoral entities has extensively been corroborated, but has also evolved with refinement or realignment of these classifications, through accruing molecular data, with many derivative ancillary diagnostic assays now already well-established. Tumors of unclear histogenesis, classically morphologically undifferentiated, are prominent amongst pediatric sarcomas, however, the classes of undifferentiated round- or spindle-cell-tumors-not-otherwise-specified are being dismantled gradually with the identification of their molecular underpinnings. Within recent years, for example, numerous subcategories of 'Ewing-like' round cell sarcoma have emerged. Such advances have provided the basis for novel diagnostic and prognostic sub-classifications. Efforts at defining cell- or lineage-of-origin for several tumor types have produced interesting insights especially for rhabdomyosarcoma. The remarkably early onset of pediatric sarcomas defies the theory necessitating stochastic accumulation of several somatic mutations for cancer development and indeed, these tumors may be remarkably genomically stable, often belying their aggressive nature. Much is coming to light recently regarding the role of epigenetic modifications in the evolution of these sarcomas. Indeed the morphologic features of embryonal tumors generally (not just sarcomas) may be highly reminiscent of arrested differentiation, and given the tight epigenetic regulation of cell fate determination and cell identity maintenance, a theory of epigenetically-driven oncogenesis sits easily with these tumors. The age-delimited distinct biologies of 'pediatric' and adult GIST are intriguing, particularly, the SDH-deficient 'pediatric' form, driven by a metabolic defect, but resulting in epigenetic dysregulation with genome-wide DNA methylation changes. There is little doubt that many of the gaps in our understanding of pediatric sarcoma biology will be filled by a deeper appreciation of the role of dysregulated epigenetics including chromatin biology, perhaps best exemplified in malignant rhabdoid tumor. The field of pediatric soft tissue tumor pathology grows ever more interesting. Importantly though, it must be emphasized, that none of this progress could have occurred, or indeed continue, without the initial step of accurate diagnosis, founded solidly on morphology - thank you Pepper for your unparalleled contributions to this field! The opportunity to be your apprentice for five years has been a bigger and more positive influence than words can express.

Ewing Sarcoma/Primitive Neuroectodermal Tumor of the Kidney: A Rare and Lethal Entity

Ewing sarcoma/primitive neuroectodermal tumor represents a spectrum of undifferentiated tumors with similar biology that together represent the second most common sarcoma in the pediatric-young adult age range. Very rarely, this tumor presents as a primary neoplasm of the kidney. The clinical presentation of this tumor is not specific, and other renal tumors may present with a similar histologic appearance. Establishing the correct diagnosis is critical because renal Ewing sarcoma/primitive neuroectodermal tumor carries a strikingly dismal prognosis and thus dictates a specific treatment strategy. A low threshold for the use of ancillary molecular tests is recommended, particularly in diagnostically problematic cases. Important considerations with regards to morphology, immunohistochemistry, and molecular alterations will be reviewed here and should be taken into account before rendering this rare and lethal diagnosis.

Primitive neuroectodermal tumour of the kidney: An unusual case mimicking renal angiomyolipoma with minimal fat

Primitive neuroectodermal tumour (PNET) is a highly aggressive neoplasm that develops classically in the central nervous system. PNET of the kidney (rPNET) is extremely rare. Recently, a 23-year-old woman complained of left flank pain and intermittent hematuria for 3 months and was admitted to our hospital. A computed tomography (CT) scan and magnetic resonance imaging demonstrated a 5.1 × 4.4-cm heterogenous mass with unconspicuous reinforcement in the upper pole of the left kidney. F18-FDG positron emission tomography CT (PET-CT) revealed the mass as a benign lesion with internal extensive bleeding. Renal angiomyolipoma with minimal fat was diagnosed. Three months later, a CT scan showed that the mass shrank to 3.1 × 2.6 cm and nephron-sparing surgery of the left kidney was performed at the patient's request. However, histologic features and immunohistochemical analysis confirmed the diagnosis of rPNET. Five cycles of combined chemotherapy were executed. At the 11-month follow-up, the patient showed no evidence of metastasis or recurrence.

A Case of Renal Primitive Neuroectodermal Tumor Confirmed by Fluorescence in situ Hybridization

Primitive neuroectodermal tumor (PNET) is a member of the Ewing's sarcoma family of tumors (ESFT). We report a case of PNET in a 66-year-old male who presented with a large solid tumor within the parenchyma of the middle pole of the left kidney with metastases to the left adrenal gland and right ischium. A fine-needle biopsy was performed and showed a small round cell tumor. Results of immunohistochemical staining suggested this tumor belonged to ESFT. Preoperative VDC-IE (combined vincristine, doxorubicin and cyclophosphamide followed by another combination of ifosfamide and etoposide) chemotherapy and left radical nephrectomy and adrenalectomy were performed. The histopathological findings of the resected tumor were similar to those in the biopsy specimen, but the results of AE1/AE3 were different. For the diagnosis, fluorescence in situ hybridization was performed. Split signals of the EWSR1 gene were detected, and transmission electron microscopy showed neuroendocrine granules and microtubules. The final diagnosis of this tumor was PNET of the kidney.

Peripheral primitive neuroectodermal tumor of the kidney in a 51-year-old female following breast cancer: A case report and review of the literature

Peripheral primitive neuroectodermal tumor/Ewing's sarcoma (pPNET/EWS) is an aggressive type of sarcoma that is rarely observed in the kidney. pPNET of the kidney principally occurs in young patients (<50 years old) and is very rare in older patients (≥50 years old). Additionally, only six cases of pPNET of the kidney have been reported in the literature in older patients (≥50 years old), and pPNET as a secondary primary tumor has rarely been reported. The current study presents a case of renal pPNET in a 51-year-old female who had been surgically treated for breast carcinoma and administered with adjuvant chemotherapy five years prior to hospitalization for pPNET. A computed tomography scan identified a tumor in the lower pole of the right kidney, which was treated by nephrectomy. Immunohistochemistry demonstrated diffuse, strong membranous positivity for cluster of differentiation (CD)99, positive nuclear staining for friend leukemia integration 1, and negative staining for Wilms' tumor 1 and other markers. Fluorescence in situ hybridization (FISH) analysis of the EWS breakpoint region 1 (EWSR1) demonstrated the characteristic EWSR1 translocation. The patient declined chemotherapy or radiotherapy but accepted traditional Chinese medicine. No evidence of recurrence was observed eight months after diagnosis. Only two cases of renal pPNET with a history of an earlier or synchronous primary cancer were reported in the literature from the USA and Germany, respectively. To the best of our knowledge, the present case is the first FISH-confirmed renal pPNET in an older patient following breast adenocarcinoma.

Treatment outcomes in 23 thoracic primitive neuroectodermal tumours: a retrospective study

OBJECTIVES

Thoracic primitive neuroectodermal tumour is an aggressive malignancy with poor survival despite multimodality treatment regimens. Early diagnosis of the tumour by histological, immunohistochemical, ultrastructural and cytogenetic techniques and early total surgical resection of the tumour with intensive chemoradiation may improve outcomes.

METHODS

Over 30 years, 23 patients (median age 29.5) with primitive neuroectodermal tumours (15 chest wall, 4 lung, 3 costovertebral sulcus and 1 anterior mediastinum) were diagnosed by transthoracic needle biopsy (43%) or excisional biopsy (57%). Treatment of a localized disease (Stage I and II) in 19 patients included surgery (wide excision of chest lesions in 11, 4 lung resections, excision of 3 costovertebral sulcus and 1 anterior mediastinal tumours, and resection of adjacent tissues involved by tumour en bloc) with adjuvant chemoradiation. Four metastatic chest wall tumours (Stage III) had chemotherapy and radiation alone.

RESULTS

Tumour recurred in 5 (2 chest wall, 2 costovertebral sulcus and 1 lung) requiring further chemotherapy, radiation and completion pneumonectomy for a lung recurrence. The incidence of recurrent tumour in 7 years for Stage I was 21 vs 40% (P=0.4) for Stage II lesions and 16% after the neoadjuvant chemotherapy vs 30% (P=0.4) after adjuvant chemoradiation. Four with recurrence, except one with a chest recurrence, succumbed to second relapse (78-96 months). All four Stage III chest tumours succumbed to advanced disease (30 months). The Kaplan-Meier disease-free survival of the overall group (23 patients) was 82±2% at 5 years and 64±3% at 10 years. The 10-year disease-free survival of 19 patients with localized tumours was 76%, but was high at 90% for chest wall tumours and low 33% for costovertebral sulcus tumours (P≤0.01). The 10-year disease-free survival was 86% for Stage I vs 60% (P=0.02) for Stage II tumours; and 83% for neoadjuvant vs 76% (P=0.06) for adjuvant chemotherapy and radiation.

CONCLUSIONS

The primitive neuroectodermal tumours are aggressive neoplasms with poor prognosis. Early diagnosis and total surgical excision of localized tumours with neoadjuvant or adjuvant chemotherapy and radiation improved disease-free survival.

Renal primitive malignant tumor with endocrine activity

OBJECTIVE

To report a hypertensive and systematically pigmented female with primitive neuroectodermal tumors.

CLINICAL PRESENTATION AND INTERVENTION

A female patient presented with a complaint of right flank pain. She had a right renal space-occupying lesion, underwent right radical nephrectomy, and returned to normotensive postoperatively. The pathological examination identified typical primitive neuroectodermal tumor histology. During a 60-month follow-up period, she remained normotensive and demonstrated normal renal and adrenal functions.

CONCLUSION

Early diagnosis and definitive surgery led to the patient's long-term survival.

Primitive neuroectodermal tumor of the kidney: a single-institute series of six patients from China

OBJECTIVE

Renal primitive neuroectodermal tumor (PNET) is a rare and highly malignant neoplasm. Our study aims to present the clinical findings and prognosis of 6 patients with renal PNET from China.

MATERIAL AND METHODS

From January 2003 to February 2012, 6 patients with renal PNET confirmed by immunohistochemical staining and fluorescence in situ hybridization (FISH) treated in our institution were reviewed retrospectively and our data compared with the literature.

RESULTS

There were 4 male and 2 female patients with a mean age of 35.0 years. The mean diameter was 13.3 cm. Five of the masses had renal vein thrombosis, and 3 extended into the inferior vena cava. A lymph node metastasis was detected in 1 patient and a liver metastasis in another patient. Radical nephrectomy was performed in all cases, with 5 patients following chemotherapy and 1 receiving Sutent treatment. Within a median follow-up of 7.5 months (range 1-71), median overall survival was 22.1 months.

CONCLUSIONS

The diagnosis of renal PNET should be considered in young patients presenting with renal mass and venous thrombosis. It seems that Asian renal PNET patients had a higher rate of venous thrombosis than Caucasian populations. CD99 positivity on immunohistochemistry and EWS-FL1 chimera gene detected by FISH support the diagnosis. The prognosis is poor despite multimodal treatment.

PNET of kidney: Report of four cases

Primitive neuroectodermal tumor (PNET) of kidney is a rare tumor of kidney with only a few published reports. We report here four cases of PNET of kidney in the age group between 30 and 50 years who had complaints of vague pain and lump in loin. Hematuria was present in one case. Imaging of all cases revealed renal mass. The pathologic findings were consistent with PNET in all cases–confirmed by immunohistochemistry with diffuse membrane positivity of tumor cells of CD99. We could not do fluorescent in situ hybridization to demonstrate EWS-FLI-1 gene fusion. Each case was in the advanced stage. However, after giving postoperative radiotherapy and chemotherapy patients are still alive. Reporting of these cases are important as we got them in a short span of 3 years. In view of its poor prognosis, aggressive nature and different therapeutic approach– renal PNET should be differentiated from other small blue round cell tumors like neuroblastoma, rhabdoid tumor of kidney, nephroblastoma, small cell carcinoma, synovial sarcoma (monophasic, poorly differentiated) and non-Hodgkin lymphoma (NHL) by immunohistochemistry, cytogenetic, and molecular genetics study to see the different gene rearrangements in NHL and 3p deletion in small cell carcinoma.

Ewing sarcoma/primitive neuroectodermal tumor of the kidney: clinicopathologic analysis of 34 cases

The present study describes the clinicopathologic analysis of 34 cases of Ewing sarcoma/primitive neuroectodermal tumor occurring in the kidney. The patients were 21 males and 13 females with an age range of 6 to 44 years. Clinically, patients presented with multiple symptoms including hematuria, pain, and/or lump in the abdomen. Nephrectomy was performed in most of the cases. Grossly, whole of the renal parenchyma was involved by a variegated tumor. Histologically, the tumor was composed of monomorphic, small, and round cells arranged in a variety of patterns. Rosettes, geographical areas of necrosis, and arborizing vascular pattern were the prominent histologic features. The nucleus was monomorphic and round. Anisonucleosis was also noted in some cases. The nucleus was mostly hyperchromatic. A mixture of hyperchromatic and powdery chromatin was noted in few cases. Immunohistochemically, MIC2 (CD99) was positive in 32 of 34 cases followed by neuron-specific enolase (9/12 cases), vimentin (8/14 cases), synaptophysin (1/8 cases), and S-100 protein (1/4 cases). Molecular analysis by reverse transcriptase-polymerase chain reaction that was carried out in 26 cases revealed presence of EWS-FLI-1 type 1 translocation in 12 cases, EWS-FLI-1 type 2 translocation in 10 cases, and both type 1 and type 2 EWS-FLI-1 translocation in 2 cases. Two cases did not demonstrate any translocation. Follow-up data were available for 17 of 34 cases. Local recurrence of the tumor was seen in 4 patients, and 10 patients were recorded to have distant metastasis in various organs, such as lung, bone, and lymph node, during the course of the disease.

Uncommon presentation of rare disorder-duodenal ulcer secondary to invasive pancreatic primitive neuroectodermal tumor: case report and review of the literature

The authors report an unusual presentation of a rare tumor in childhood, a pancreatic primitive neuroectodermal tumor invading the duodenum leading to anemia. A review of intra-abdominal primitive neuroectodermal tumors is discussed.

Primary Ewing's sarcoma/primitive neuroectodermal tumor of the kidney: Report of a case diagnosed by fine needle aspiration cytology and confirmed by immunocytochemistry and RT-PCR along with review of literature

Primary Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) of the kidney is a distinct entity that can be mistaken for variety of round cell tumors. We report a rare case of ES/PNET of the kidney in a 35-year-old female patient diagnosed by fine needle aspiration cytology (FNAC) and confirmed by immunohistochemistry (IHC) and reverse-transcriptase polymerase chain reaction (RT-PCR). Ultrasound guided FNAC smears from the kidney mass showed a population of malignant small round cells with perivascular arrangement and focal rosette formation. IHC performed on the cell block, showed strong immunopositivity for CD99 (MIC2) and vimentin. Molecular analysis of the aspirate by RT-PCR confirmed the EWS-FLI type1 transcript. The application of RT-PCR on FNAC material for establishing a diagnosis of renal ES/PNET is being reported for the first time. FNAC also confirmed metastases in the right level I cervical lymph node. The utility of IHC and molecular techniques in diagnosis of such a rare case is stressed and relevant literature is discussed.

Cardiac metastasis: a rare involvement of primitive neuroectodermal tumour of the lung

A 15 year-old adolescent was referred with 2 month history of worsening of breathlessness and haemoptysis. He also reported constitutional symptoms of fever, poor appetite and weight loss. The chest roentgenogram showed a massive right pleural effusion with apparent cardiomegaly. The cardiac silhouette over the right heart border was obliterated and the mediastinum was widened. Computed tomogram of the thorax showed a bulky heterogeneous mass in the right lung with extension to the heart. Subsequent CT guided lung biopsy revealed Primitive Neuroectodermal tumour (PNET). Here, we illustrate the clinical course of an aggressive pulmonary PNET with lethal cardiac metastasis.

Ewing sarcoma: an eponym window to history

Ewing sarcoma was named after James R. Ewing, an eminent American pathologist at Cornell who described the first cases in 1921. Although he is best remembered for this singular achievement, Ewing's contributions to the study of cancer were far more profound and influential. He essentially launched oncology as a discipline with the publication of his seminal textbook and founded the major American cancer societies that exist today. His vision of comprehensive cancer centers still drives our research infrastructure. Since his initial report, these organizations have helped us achieve numerous milestones in understanding and treating patients with Ewing sarcoma.

Renal primitive neuroectodermal tumour in childhood: Case report and review of literature

Primitive neuroectodermal tumour (PNET) is presumed to be of neural crest origin, mostly presenting as bone or soft tissue masses. It usually occurs in the trunk or axial skeleton; while renal PNET is considered an extremely rare tumour. We report a case of 11-year-old male who presented with right flank pain and gross hematuria after suffering blunt trauma. During investigations, he was found to have a large renal mass on computed tomography. He underwent a right radical nephrectomy where the pathology report showed PNET of the kidney. The patient received chemotherapy afterwards. Despite the chemotherapy, he had a local tumour recurrence 3 months after and continued to deteriorate and developed distant metastasis. Primitive neuroectodermal tumour of the kidney is a distinct and rare entity. It is very aggressive, with a poor survival despite combined modality treatment.

Ewing's sarcoma of the kidney

Primitive neuroectodermal tumors (PNETs) are small, round-cell tumors of neural crest origin classically found in the central nervous system (CNS) but more recently characterized in the periphery. Peripherally located PNETs (pPNETs) are members of the Ewing's sarcoma family of tumors (EFTs). Renal localization of pPNETs is very rare, is found in young adults, and is characterized by an aggressive clinical course and poor prognosis. We present the case of a young man with renal pPNET characterized by psuedorosette formation, cluster of differentiation 99 (CD 99+), focally positive for neuron-specific enolase (NSE), with cytogenetic findings of the translocation t(11;22)(q24;q12) and the unique abnormality of trisomy 7. To our knowledge, we report the first case of trisomy 7 and PNET.

Primitive neuroectodermal tumor of the liver: a case report

Ewing sarcoma/primitive neuroectodermal tumor is a rare tumor of soft tissues of thoraco-pulmonary regions, pelvis and lower extremities. Involvement of visceral organs by primitive neuroectodermal tumor is even rarer, with the kidney being the most commonly involved organ. Involvement of the liver has been reported in the form of metastasis from other primary sources presenting as liver abscess. We report a 20-year-old lady presenting with massive hepatomegaly, with computed tomography scan evidence of diffuse hepatomegaly and a normal porta and intrahepatic biliary radicles. She subsequently underwent ultrasonography-guided true-cut needle biopsy of the liver. Histopathology of the liver revealed nests of small round blue tumor cells in the background of hepatocytes infiltrating the liver, which expressed Mic-2 and Fli-1, and were negative for cytokeratin, desmin, hepatocyte-specific antigen (OCHIE5), synaptophysin, chromogranin A and CD-20. Immunohistochemistry revealed CD-99-positive. Extensive search regarding any possible different site of involvement by the tumor was negative. The patient responded to a combination therapy of vincristine, adriamycin and cyclophosphamide alternating with ifosfamide and etoposide 3 weekly over 43 weeks and has been doing well even after 1 year of diagnosis. The clinical presentation, the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype lead to the diagnosis of primary primitive neuroectodermal tumor of the liver which responded well to combination chemotherapy.

Primitive neuroectodermal tumor of the kidney in an adult: a case report

INTRODUCTION

Primitive neuroectodermal tumors (PNETs) occur predominantly in childhood preferentially in the soft tissues of the lower extremity and the paraspinal region. We present here a rare case of a PNET of the kidney in an adult.

CASE PRESENTATION

A tumor adjacent to the right kidney was detected by ultrasound coincidentally at a routine check-up in a 46-year-old woman with irritable bowel syndrome in her medical history. The patient had no clinical signs. Contrast-enhanced computerized tomography scan of the abdomen demonstrated a highly vascularized renal tumor. A retroperitonealectomy with en-bloc resection of the kidney was performed, and histopathological work-up showed a primitive neuroectodermal tumor of the kidney with the characteristic translocation t(11;22)(q24;q12).

CONCLUSION

This tumor entity must be accurately distinguished from other renal neoplasms because of the prognostic and therapeutic impact.

Primitive Neuroectodermal Tumor of the Kidney with Hyaline Cells

Primitive neuroectodermal tumor (PNET) of the kidney is a rare disease with high malignant potential. It affects young adults and has the tendency towards early metastasis. Relying on recently available immunohistochemistry and cytogenetic investigations, today most authors define PNET as part of the same nosologic entity as Ewing's sarcoma. We present the case of a 22-year-old man with a PNET arising from the kidney with, to our knowledge, a previously undescribed finding of hyaline cells within the tumor.

Primitive neuroectodermal tumor of the kidney: a single institute series of 16 patients

OBJECTIVES

Primitive neuroectodermal tumor (PNET) of the kidney is a rare entity, the diagnosis usually being made at histopathology. Few cases reported in literature revealed a variable presentation and an aggressive behavior. The purpose of our study was to review our experience in diagnosis and the management of patients with renal PNET.

METHODS

The records of 16 patients of renal PNET treated between 1995 and 2003 were reviewed retrospectively and our data compared with the literature.

RESULTS

There were 10 male and 6 female patients with median age of 27 years. At presentation, 10 patients (63%) had localized disease, 5 (31%) had metastatic disease and 1 (6%) had locally advanced disease. The presence of Homer-Wright type rosettes on hematoxylin and eosin staining and CD99 (cluster differentiation) products positivity on immunohistochemistry supported the diagnosis. Radical nephrectomy was performed in operable cases and all patients received chemotherapy. Nine patients received adjuvant radiotherapy to the renal bed. Median follow-up was 31 months (range 4 to 92). Overall median survival was 40 months with 3- and 5-year survival of 60% and 42%, respectively.

CONCLUSIONS

The diagnosis of renal PNET must be considered in young patients presenting with renal mass. Standard therapy consists of combination of surgical resection, postoperative irradiation and chemotherapy. Chemotherapy regimen used is either RCT II (round cell tumor) protocol or EFT 2001 (Ewing's family of tumors) protocol. However, further studies are required to validate the appropriate chemotherapy protocol.

Primitive neuroectodermal tumor of the breast: immunohistochemistry and fluorescence in situ hybridization

A case of primitive neuroectodermal tumor (PNET) that developed as a breast lump in a 47-year-old Japanese woman is reported. After fine-needle aspiration (FNA) cytology, a mastectomy was performed. The surgical specimen was a well-circumscribed tumor, 21 x 18 x 18 mm, localized in the breast. The tumor cells were small and round with scant cytoplasm, and proliferated in sheets or solid nests. No intraductal carcinoma component was present. The tumor cells were immunohistochemically positive for neural cell adhesion molecule (CD56), neuron-specific enolase and synaptophysin, and they showed membranous immunoreactivity for the MIC2 protein (CD99). Fluorescence in situ hybridization (FISH) indicated a rearrangement of the EWS region on chromosome 22, which is highly specific for Ewing's sarcoma and PNET, which are referred to as the Ewing's sarcoma family of tumors (EFT). No other lesions suggestive of the primary site of this tumor, such as bone, soft tissue, or other organs were detected. The patient has been disease free for 6 months after surgery followed by chemoradiation therapy. FISH is extremely useful for accurate diagnosis of EFT, especially in cases of unusual locations.

Recently Described and Emphasized Entities of Renal Neoplasms

Context.—Recent advances of molecular biology and cytogenetics of renal cancer have resulted in the new classification of renal neoplasms and a number of subtypes are identified and emphasized. In addition, rare nonepithelial renal neoplasms are identified and characterized. Familiarity with these entities will help make the most accurate diagnosis and guide the treatment and follow-up of patients with renal neoplasm.

Objective.—To review the clinicopathologic entities of renal neoplasms that are recently defined or emphasized. Their clinical, gross, microscopic, and immunohistochemical features, as well as specific cytogenetic or molecular abnormalities, are discussed. Important differential diagnoses of each entity are also briefly discussed.

Data Sources.—Extensive review of published literature and our experience.

Conclusions.—A number of new entities of renal neoplasms or genetically defined renal cell carcinomas have been identified or emphasized because of their unique genetic or molecular changes. Recognition of these entities becomes important as some of them have different biologic behavior and treatment strategies may be different.

Cytologic diagnosis of Ewing sarcoma/peripheral neuroectodermal tumor with paired prospective molecular genetic analysis

BACKGROUND

Ewing sarcoma/peripheral neuroectodermal tumor (EWS/PNET), since its characterization immunophenotypically and cytogenetically, has emerged as one of most common sarcomas of childhood. Currently, it is recognized that EWS/PNET can occur in any number of extraosseous sites and is one of several distinctive tumor types with an EWS translocation. In the past, the pathologic diagnosis of EWS/PNET relied on an open biopsy with the application of various ancillary studies, ranging from periodic acid-Schiff stain to molecular testing, but the tumor increasingly is diagnosed on the basis of cytologic specimens alone.

METHODS

The authors report 3 cases of EWS/PNET in patients aged 11 years to 53 years. These 3 patients had tumors that involved the parotid gland, cervical soft tissue, and pelvis, and were diagnosed by cytologic evaluation of fine-needle aspiration (FNA) biopsy material alone. The FNA materials also were evaluated prospectively by fluorescence in situ hybridization and/or reverse transcriptase-polymerase chain reaction.

RESULTS

The results emphasized the diagnostic utility of FNA biopsy material for morphologic and molecular analysis without compromising conventional cytologic and immunocytochemical analysis, and that prospective molecular testing of FNA specimens has utility in routine practice although it is subject to many of the same limitations that impact molecular analysis when applied to conventional tissue biopsy specimens.

CONCLUSIONS

The current results demonstrated that molecular genetic techniques can provide clinically useful ancillary information for FNA specimens when cytologic features and/or immunophenotype are equivocal on the basis of limited sampling or secondary changes, such as hemorrhage and/or necrosis.

Primary Ewing sarcoma/PNET of the kidney: fine-needle aspiration, histology, and dual color break apart FISH Assay

A 34-year-old previously healthy Hispanic man presented with lower back pain. CT scan revealed an 8-cm space-occupying lesion in the superior pole of the left kidney with numerous small lytic lesions in the skull, vertebrae, ribs, and pelvic bones. CT-guided fine-needle aspiration biopsy revealed a high-grade primitive small round cell tumor with the tumor cells being strongly positive for CD99 and vimentin. The patient subsequently underwent a left nephrectomy. Fluorescence in situ hybridization analysis using a DNA probe for the Ewing Sarcoma breakpoint region 1 (EWSR1) on chromosome 22g12 revealed a rearrangement of the EWSR1 locus. The diagnosis of primary Ewing sarcoma/primitive neuroectodermal tumor of the kidney was established.

A spontaneously ruptured primitive neuroectodermal tumor/extraosseous Ewing's sarcoma of the kidney with renal vein tumor thrombus

Primitive neuroectodermal tumor/extraosseous Ewing's sarcoma (PNET/EES) is a childhood disease rarely seen in adults. It is a soft tissue tumor, which is often observed in the paraspinal region and lower extremity. We report the case of a 32-year-old man who presented with sudden abdominal pain on the right upper quadrant that was radiated to the right flank. During the operation, a spontaneously ruptured right kidney mass was found. The histopathologic and immunohistochemical characteristics of the excised mass were consistent with PNET/EES. This is the first known reported case of spontaneously ruptured PNET/EES of the kidney with renal vein tumor thrombus. The clinical details and the management of this case are described.

Metastatic primitive neuroectodermal tumor of the ovary in pregnancy

Primitive neuroectodermal tumor (PNET) is a small round tumor belonging to the PNET/Ewing's sarcoma family. We hereby report a case of PNET of the ovary, which was detected at the second trimester of pregnancy. Chemotherapy was administered and a healthy baby was delivered by cesarean section. After the pregnancy, the mother was found to have metastatic disease. Chemotherapy was continued, but she died due to progressive disease 13 months after the initial diagnosis. In this case report, we discuss chemotherapy options during pregnancy and the importance of multidisciplinary approach to unusual presentations of rare tumors

Ewing's sarcoma family of tumors: current management

Ewing's sarcoma is the second most frequent primary bone cancer, with approximately 225 new cases diagnosed each year in patients less than 20 years of age in North America. It is one of the pediatric small round blue cell tumors, characterized by strong membrane expression of CD99 in a chain-mail pattern and negativity for lymphoid (CD45), rhabdomyosarcoma (myogenin, desmin, actin) and neuroblastoma (neurofilament protein) markers. Pathognomonic translocations involving the ews gene on chromosome 22 and an ets-type gene, most commonly the fli1 gene on chromosome 11, are implicated in the great majority of cases. Clinical presentation is usually dominated by local bone pain and a mass. Imaging reveals a technetium pyrophosphate avid lesion that, on plain radiograph, is destructive, diaphyseal and classically causes layered periosteal calcification. Magnetic resonance best defines the extent of the lesion. Biopsy should be undertaken by an experienced orthopedic oncologist. Approximately three quarters of patients have initially localized disease. About two thirds survive disease-free. Management, preferably at a specialist center with a multi-disciplinary team, includes both local control-either surgery, radiation or a combination-and systemic chemotherapy. Chemotherapy includes cyclic combinations, incorporating vincristine, doxorubicin, cyclophosphamide, etoposide, ifosfamide and occasionally actinomycin D. Topotecan in combination with cyclophosphamide has shown preliminary activity. Patients with initially metastatic disease fare less well, with about one quarter surviving. Studies incorporating intensive therapy followed by stem cell infusion show no clear benefit. New approaches include anti-angiogenic therapy, particularly since vascular endothelial growth factor is an apparent downstream target of the ews-fli1 oncogene.

Primary Ewing's sarcoma family of tumors arising from the broad ligament

We report a case of a primary Ewing's sarcoma family of tumors (ESFT) that was an incidental finding in the broad ligament of a 53-year-old woman. ESFT now includes tumors previously described as Askin tumor, neuroepithelioma, extraskeletal Ewing's sarcoma, and peripheral primitive neuroectodermal tumor. This is because of the discovery that all of the above tumors contain a specific gene rearrangement involving chromosome 22q12. On microscopic examination, the tumor was composed of small, round cells with mild nuclear pleomorphism and scant eosinophilic cytoplasm. There were large areas of tumor necrosis and numerous mitoses. Immunohistochemically, there was strong membrane staining for CD99 and weak focal staining for CD56 and neuron specific enolase. Fluorescence in situ hybridization revealed a separation of the breakapart probe on chromosome 22q12 consistent with the presence of a gene rearrangement, supporting the diagnosis of ESFT. We believe the importance of recognizing the existence of a primary ESFT in the broad ligament as some primary tumors of the gynecological tract and of other systems may resemble it histologically. To the best of our knowledge, our case is the second case of extraskeletal Ewings sarcoma arising from the broad ligament but the first case that is confirmed by strong CD99 positivity and supported by fluorescence in situ hybridization.

A practical approach to the clinical diagnosis of Ewing's sarcoma/primitive neuroectodermal tumour and other small round cell tumours sharing EWS rearrangement using new fluorescence in situ hybridisation probes for EWSR1 on formalin fixed, paraffin wax embedded tissue

BACKGROUND

Over 90% of Ewing's sarcoma/primitive neuroectodermal tumour (ES/PNET) cases have the t(11;22) chromosomal rearrangement, which is also found in other small round cell tumours, including desmoplastic small round cell tumour (DSRCT) and clear cell sarcoma (CCS). Although this rearrangement can be analysed by fluorescence in situ hybridisation (FISH) using routinely formalin fixed, paraffin wax embedded (FFPE) tissues when fresh or frozen tissues are not available, a sensitive and convenient detection method is needed for routine clinical diagnosis.

AIMS

To investigate the usefulness of newly developed probes for detecting EWS rearrangement resulting from chromosomal translocations using FISH and FFPE tissue in the clinical diagnosis of ES/PNET, DSRCT, and CCS.

METHODS

Sixteen ES/PNETs, six DSRCTs, and six CCSs were studied. Three poorly differentiated synovial sarcomas, three alveolar rhabdomyosarcomas, and three neuroblastomas served as negative controls. Interphase FISH analysis was performed on FFPE tissue sections with a commercially available EWSR1 (22q12) dual colour, breakapart rearrangement probe.

RESULTS

One fused signal and one split signal of orange and green, demonstrating rearrangement of the EWS gene, was detected in 14 of 16 ES/PNETs, all six DRSCTs, and five of six CCSs, but not in the negative controls.

CONCLUSIONS

Interphase FISH using this newly developed probe is sensitive and specific for detecting the EWS gene on FFPE tissues and is of value in the routine clinical diagnosis of ES/PNET, DSRCT, and CCS.

Tubulocystic Carcinoma, Mucinous Tubular and Spindle Cell Carcinoma, and Other Recently Described Rare Renal Tumors

In the past 10 years, several new renal tumors have been identified. Some have been reviewed in this article, and others have been reviewed elsewhere in this issue. Most have been included in the 2004 edition of the WHO classification of tumors of the urinary system and male genital organs. Tubulocystic carcinoma needs to be studied and characterized more fully.

Peripheral primitive neuroectodermal tumor of the stomach in a 14-year-old boy: a case report

Although PNETs are rare malignancies, they should be considered in the differential diagnosis of submucosal gastric tumours in adolescents with clinical alarm symptoms.NET was confirmed by detection of the characteristic EWS/FLI-1 fusion gene, resulting in a reciprocal translocation t(11;22)(q24;q12). Three distinct liver metastases were detected by CT, MRI, and PET. The tumour failed to respond to neoadjuvant polychemotherapy with vincristine, etoposide, doxorubicin, and ifosfamide. Subtotal gastrectomy was performed and, surprisingly, we found diffuse metastatic infiltration of the liver that had not been detected by preoperative staging. Due to the diffuse metastatic disease the young patient's prognosis has to be considered very poor. Because of the tumour's intense expression of CD117 (c-kit), the patient is now treated with the tyrosine kinase inhibitor imatinib (STI571).

Primitive neuroectodermal tumor of the gallbladder

Ewing sarcoma/primitive neuroectodermal tumor (ES/ PNET) most commonly occurs in the soft tissues of the extremities and the paravertebral areas. To our knowledge, no case of PNET has been reported in the gallbladder to date. We report a case of PNET of the gallbladder occurring in a 53-year-old woman. Microscopically, the monotonous small round cells with a formation of Homer-Wright rosettes showed intense membranous positive immunoreactivity for MIC2/CD99, as well as for neuron-specific enolase and synaptophysin. Other small round cell tumors, such as lymphoma, rhabdomyosarcoma, or melanoma, were excluded in light of negative immunoreactivity for leukocyte common antigen, desmin, and S100. The diagnosis of PNET was rendered based on the characteristic morphology and immunohistochemical findings, despite an absence of chromosomal translocations, such as t(11; 22)(q24;q12) and t(21;22)(q22;q12).

A case of peripheral primitive neuroectodermal tumor of the ovary

Peripheral primitive neuroectodermal tumor (PNET) belongs to the PNET/Ewing's sarcoma family. PNET is a small round cell tumor of putative neuroectoderm origin and is the second most common sarcoma among children and young adults. It may occur anywhere in the body and within any age group; however, it is most likely to occur in the bone and soft tissues. There have been a small number of case reports of PNET arising in the ovary. We presented a case of PNET arising in the right ovary of an 18-year-old woman. The tumor was metastased to the lymph nodes of the pelvis and para-aorta at surgical staging. We had persecuted Taxol/carboplatin chemotherapy, pelvic cavity radiotherapy, and Vincristine/Actinomycin, Cyclophosphamide/Doxorubicin (VACA). She died after 10 months due to septic shock.

Findings and clinical course of a localized primitive peripheral neuroectodermal tumor of the kidney

Primitive neuroectodermal tumor (PNET) is a very aggressive neoplasm, considered to have an unfavorable prognosis, and renal location is extremely rare. We present the findings and clinical course of a patient with localized disease who is free of disease more than 3 years after first presentation. In suspicious cases we recommend to surgically explore renal masses as early as possible.

[Primary renal synovial sarcoma. A new entity in the morphological spectrum of spindle cell renal tumors]

We report 2 primary renal synovial sarcoma. These tumors were formerly designated as embryonal cystic sarcoma of the kidney. Most cases are diagnosed between the ages of 20 and 50 years. Some cases show local recurrence after nephrectomy. On gross examination, tumors are large, partially necrotic, and usually contain cysts. Microscopically, tumors are characterized by monomorphic plump spindle cells. The cysts are lined by mitotically inactive epithelial cells without striking cellular atypia. The spindle cells were immunoreactive for EMA, CD56, and sometimes for CD99. They were non-reactive for desmin, actin, S 100, and cytokeratins. The cyst epithelium is cytokeratin positive. The presence of a SYT-SSX gene fusion resulting from the t(X;18) characteristic for synovial sarcoma was demonstrated by reverse transcriptase polymerase chain reaction in both tumors. Primary renal synovial sarcoma is a distinctive tumor entity, which should be considered in renal tumors consisting of spindle cells.

Recent advances in pediatric renal neoplasia

Over the past 6 years, molecular genetic studies have significantly advanced our understanding of pediatric renal neoplasms. The cellular variant of congenital mesoblastic nephroma (but not the classic variant) has been shown to bear the same t(12;15)(p13;q25) and ETV6-NTRK3 gene fusion as infantile fibrosarcoma, a tumor with which it shares morphologic and clinical features. Rhabdoid tumor of the kidney is characterized by deletion of the hSNF5/INI1 gene, which links it to other rhabdoid tumors of infancy that arise in the soft tissue and brain. Primary renal synovial sarcomas and renal primitive neuroectodermal tumors have become accepted entities, and likely comprise a subset of what had previously been termed "adult Wilms tumor." Renal carcinomas associated with Xp11.2 translocations that result in fusions involving the TFE3 transcription factor gene have been delineated, including a distinctive neoplasm that shares the identical gene fusion as alveolar soft part sarcoma. Most recently, a distinctive type of renal neoplasm with a t(6;11)(p21;q12) has been described, and the cloning of the resulting gene fusion links it to the Xp11 translocation carcinomas. Together, these last two translocation-associated tumors represent a significant proportion of pediatric renal cell carcinomas. This review highlights each of these recent advances.

Primitive neuroectodermal tumor (PNET) in the differential diagnosis of malignant kidney tumors

Primitive neuroectodermal tumors (PNETs) of the kidney, a rare neoplastic disease of high malignancy with a tendency towards early metastasis, affect young adults (26-30 years) irrespective of the gender. Differential diagnosis from other renal tumors is very important for an effective therapy. Herein, we report on a 24-year-old male patient with a renal tumor consisting of small, round cells, and summarize the diagnostic procedures that establish the diagnosis of PNET. Light microscopy revealed not only areas containing small, round cells forming rosettes and pseudorosettes, but also areas containing spindle cells. Expression of CD 99 in combination with neural markers, such as NSE, was detected by immunohistochemistry, and further evidence of neural differentiation was provided by electron microscopy. Image cytometry revealed a peridiploid DNA-stemline. A reciprocal translocation of the chromosomes 11 and 22 [t(11;22)(q24;q12)] with expression of a EWS/FLI-1 fusion transcript was demonstrated by molecular pathology. Using these methods, the diagnosis of PNET was firmly established, and the tumor was treated by surgical resection and subsequent adjuvant chemotherapy. Eighteen months after therapy, the patient is in excellent health condition without any evidence of tumor recurrence.