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

Primitive Neuroectodermal Tumor Presenting With a Large Subcapsular Hematoma in Pregnancy: A Case Report and Current Literature Review

Primitive neuroectodermal tumors (PNET) are rare, small round cell tumors that are difficult to diagnose. It is important to identify PNET early, utilizing immunohistochemistry and genetic markers, as it is often an aggressive cancer. PNET is most commonly described in men between the ages of 20 and 40, with very few case reports highlighting the development in pregnant patients. We present a case of localized renal PNET in a pregnant patient and highlight the diagnostic work-up and treatment as well as the relationship between pregnancy and the potential development of aggressive tumors.

Experience of CT diagnosis and management of primary renal Ewing's sarcoma: A retrospective analysis of 6 cases and a literature review

To present the clinical experience of primary renal Ewing's sarcoma/primitive neuroectodermal tumors (rEWs/PNET) admitted to our hospital and systematically review the published literature. A retrospective analysis was performed on patients with pathologically confirmed renal EWs/PNET (rEWs) in our hospital, and the literature on rEWs published in PubMed and Embase databases before March 1, 2022 was searched for analysis. A total of 337 rEWs were included in the statistical analysis, including 6 cases of our patients and 331 cases published in the literature. The common clinical symptoms of rEWs are abdominal pain, hematuria, abdominal mass and so on. computed tomography (CT) plays an important role in the diagnosis of rEWs, and the typical manifestation is a large heterogeneous soft tissue density mass, with a specific "septum-like" enhancement in contrast-enhanced scan. The 2-year overall survival rate of rEWs was 48%, with a median survival time of 18 months. "Septum-like" enhancement on CT can be used as a relatively specific sign for the differential diagnosis of rEWs from Wilms tumor and neuroblastoma. The maximum diameter of the rEWs was usually greater than 10 cm, the clinical symptoms of weight loss, metastasis at diagnosis, tumor thrombogenesis of renal vein or/and inferior vena cava tumor, and the failure to undergo radical nephrectomy were the factors of poor prognosis. The incidence of primary rEWs is low and the prognosis is poor. Early diagnosis and radical nephrectomy combined with chemotherapy is the key to improve the prognosis of patients, and CT plays an important role in early diagnosis.

A rare case of retroperitoneal primitive neuroectodermal tumor (PNET)

Retroperitoneal primitive neuroectodermal tumors (PNET) is a rare neoplastic disease of high malignancy with a tendency towards early metastasis, affect young adults irrespective of the gender. We present 81 year old woman, who was admitted in the Urology Department with symptoms of right flank pain and hematuria. Contrast-enhanced computerized tomography scan (CT-scan) showed a large heterogeneous right kidney mass around 12 cm in diameter. The final diagnosis of primitive neuroectodermal tumor (PNET) was established based on clinical, pathological, and molecular results.

Primary primitive neuroectodermal tumor of the kidney

Renal primitive neuroectodermal tumor (PNET) is a rare entity. It should be differentiated from other primary renal malignancies. The differentiation of the malignant small round cell tumors may be challenging; however, it is essential for better management of the patient. We report a 45-year-old male having complaints of pain in the abdomen, hematuria, and mass in the abdomen for 6 months. Abdominal and pelvic sonography finding showed cystic-solid, right renal mass suggestive of malignancy. On histopathology diagnosed as malignant small round blue cell tumor suggestive of primitive neuroectodermal tumor. On immunohistochemistry, CD99 positivity confirmed the diagnosis of primary PNET of the kidney. We are presenting this case for its rarity, clinical presentation, and pathological findings.

Primary renal primitive neuroectodermal tumor

Primitive Neuroectodermal Tumor of the kidney is a rare entity. Very few cases of primary renal PNET have been reported to date. Most literature about rPNET is isolated case reports. We report a case of rPNET in a 39-year-old male with a pre-operative diagnosis of renal cell carcinoma with renal vein thrombosis. The patient underwent radical nephrectomy with thrombolectomy, and histopathological examination revealed a highly aggressive tumor composed of monotonous sheets of round cells. Tumor cells were positive for CD 99 and FLI-1, hence confirming the diagnosis of Primitive Neuroectodermal Tumor. Post-surgery, patient was given VAC/IE-based adjuvant chemotherapy. In view of highly aggressive nature of this tumor, prompt diagnosis and imparting effective chemotherapy regimen to the patient is required, and it is important to differentiate PNET from other small round-cell tumors because of different therapeutic approach.

Renal Primitive Neuroectodermal Tumor: A Case Report

Primitive neuroectodermal tumor (PNET) is a malignant small round cell tumor and typically arises from bone or soft tissue in adolescents and young adults. Renal PNET is extraordinarily rare and exhibits highly aggressive biological behavior with poor prognosis.We present here a new case of renal PNET in a 31-year-old female. The patients were referred to our hospital because of left flank pain with nausea and vomiting for 1 week. A computed tomography scan revealed a 14.7 × 12.7 cm well-defined, unevenly mass lesion with both solid and cystic components and the tumor was not enhanced uniformly.A preoperative diagnosis of cystic renal cell carcinoma and urinary tract infection was made. The patient undergone anti-inflammatory therapy followed by a left radical nephrectomy. Taken with morphological pattern and immunohistochemical markers, a diagnosis of renal PNET was made. Two cycles of combined chemotherapy were executed. At the 14-month follow-up, no evidence of metastasis or recurrence was indicated.This case reminds clinicians that for adolescents and young adults with a suspicious renal mass, a diagnosis of renal PNET should be always considered. An initial surgery followed by radiotherapy and chemotherapy is suggested for the therapeutic management.

Primitive neuroectodermal tumor of the kidney in a young male: Case report and review of literature

Primitive neuroectodermal tumor of the kidney is a rare tumor. A total of approximately 79 primary renal cases have been reported to date. Primitive neuroectodermal tumors occur preferentially in the soft-tissues of the paravertebral region and chest wall, less frequently in extremities, with a slight male predominance. We report a case of primitive neuroectodermal tumor of the kidney in a 17-year-old male with a pre-operative diagnosis of renal cell carcinoma-stage 4. The patient underwent radical nephrectomy and histopathological examination revealed a highly aggressive tumor of monotonous sheets of round cells with focal areas of rosette formations and high mitotic rate with Ki67 index of 25-30%. Tumor cells were positive for CD 99 confirming the diagnosis of primitive neuroectodermal tumor. Primitive neuroectodermal tumor of the kidney needs to be kept in mind as a differential diagnosis in young adults presenting with a large kidney mass.

Renal Ewing tumors

BACKGROUND

Renal Ewing's sarcoma/primitive neuroectodermal tumor (ES/PNET) is extremely rare. Clinical symptoms are nonspecific presenting abdominal pain, palpable mass, and hematuria. Owing to advanced technology demonstrating the ES-specific EWS/ETS translocation, this differential diagnosis has become feasible.

PATIENTS AND METHODS

The German database of GPOH Ewing's sarcoma trials from 1980 to 2009 was searched for kidney as primary site. Twenty-four patients were identified and analyzed. The median time of observation was 3.71 years (range 0.27-8.75 years). Additionally, we carried out a Medline search for renal ES/PNET.

RESULTS

The median age was 24.9 years (range 11-60 years). In 37.5%, patients presented with primary metastases. Tumor thrombi in the adjacent renal vessels occurred in 56.2%. In 90.9%, rearrangements of t(11;22) were found. All patients received a combined chemotherapy according to the EURO-E.W.I.N.G.99 protocol. In accordance, local control consisted predominantly of combined modality surgery and radiation (47%). At 3 years, overall survival (OS) was 0.80 (SE = 0.09), and event-free survival (EFS) 0.66 (SE = 0.11).

CONCLUSIONS

ES/PNET should be considered in the differential diagnosis of renal tumors. Patients with renal ES/PNET respond to and benefit from conventional ES treatment according to ES study protocols. Therefore, an accurate diagnostic approach and a guideline-adapted therapy should be facilitated.

Bilateral ewing sarcoma/primitive neuroectodermal tumor of the breast: a very rare entity and review of the literature

Peripheral primitive neuroectodermal tumors (PNET) are rare malignant tumors, affecting mostly children and adolescents and have been described in breast in eight case reports only. In this paper, we present a case of bilateral mammary ES/PNET where distinction between primary and metastatic diseases was discussed through a literature review. The aim of this work is to demonstrate that although rare, the possibility of PNET should be kept in mind while evaluating a palpable breast abnormality in a young female.

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.

Renal primitive neuroectodermal tumor: does age at diagnosis impact outcomes?

Primitive neuroectodermal tumor (PNET) of the kidney is a rare and highly malignant neoplasm. The median age for renal PNET is 27 years but it can be seen also in a wide age range between 3 and 78 years. We performed a Medline search for the term renal PNET and identified 79 cases up till December of 2010. We report here a new case of renal PNET and a literature review for published data for evaluation of clinicopathological prognostic factors, with an emphasis on prognosis in two groups of adults and children-adolescents: 18 years of age or under and over 18 years.

Metastatic Ewing's sarcoma/PNET of kidney in 40 year old patient

INTRODUCTION

Primary renal Ewing sarcoma/PNET is an uncommon and very aggressive tumor.

PRESENTATION OF CASE

: We report the case of a young woman who underwent nephrectomy for a renal mass from unknown etiology. Histologic analysis found small tumoral cells in rosette formation, and immunohistochemical staining was positive for CD99, and focally positive for vimentin and Protein S-100. A post operative abdominal computed tomography (CT) scan revealed a residual renal processus with hepatic wounds and abdominal metastatic nodes. After 6 cycles of chemotherapy including Vincristine, Doxorubicin, Cyclophosphamide, the response was considered as good.

DISCUSSION

Ewing's sarcoma/PNET of kidney is a member of the family of small round cell tumors and it should be differentiated from Wilms tumor, neuroblastoma, rhabdomyosarcoma and lymphoblastic lymphoma. The principle management of its treatment have been extrapolated from the treatment of osseous Ewing sarcoma of bone.

CONCLUSION

Despite aggressive treatment, primary renal Ewing sarcoma/PNET has a poor prognosis. It requires a multidisciplinary approach including oncologists, urologists and radiation oncologists.

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 kidney]

Primitive neuroectodermal Tumor (PNET) is a rare malignant tumor of young adult. Patients often present with the classical trias of renal cancer (pain, haematuria, palpable tumor). Specific radiological signs are missing, and therefore a PNET is often diagnosed postoperatively. It is characterized by the expression of MIC2, neural markers (Vimentin, S-100, Synaptophysin) and EWS/FLI1-translocation. The tumor is often diagnosed in advanced stage, and prognosis is poor despite of multimodal treatment including radical nephrectomy, polychemotherapy (vincristine, adriamycin, cyclophosphamid, etoposide, ifosfamide) and radiation in case of metastases or incomplete resection of primary tumor. We represent two cases of metastatic renal PNET in a 28- and 39-year-old patient. Due to the multimodal treatment a partial and a complete remission was achieved, respectively.

Primitive neuroectodermal tumor: rare, highly aggressive differential diagnosis in urologic malignancies

OBJECTIVES

Peripheral primitive neuroectodermal tumor (PNET) is a highly aggressive neoplasm belonging to the Ewing family of tumors. It is characterized by the expression of MIC2 and neural markers (eg, neuron-specific enolase, synaptophysin, S-100, vimentin, Leu-7), and the presence of the EWS-FLI1 translocation.

METHODS

We performed a MEDLINE search for PNET in urologic malignancies. Additionally, we report on 2 cases of renal and 1 case of bladder PNET. The data obtained by reviewing patients with renal PNET were analyzed using Kaplan-Meier analysis.

RESULTS

Renal PNET is diagnosed in young adults (median age 24 years). In contrast, the incidence of bladder PNET seems to be dependent on a defective immune mechanism. Patients often present with pain (84%), palpable tumor (60%), and hematuria (38%). The radiologic findings are uncharacteristic; therefore, the diagnosis should be based on the histologic and immunohistochemistry findings. Renal and bladder PNET are both often diagnosed at an advanced stage and, therefore, the prognosis is poor, despite aggressive multimodal treatment (surgery, polychemotherapy, radiotherapy). We identified palpable tumor masses (log-rank test, P = 0.0027) and synaptophysin expression (log-rank test, P = 0.0422) as prognostic unfavorable markers for renal PNET.

CONCLUSIONS

Renal PNET should be considered in young patients who present with the classic triad of renal cancer, hematuria, and pain and palpable tumor. Once PNET is diagnosed, multimodal treatment (radical surgery, multidrug chemotherapy, radiotherapy) must be initiated. Despite this, the prognosis is poor if distant metastases are present. Furthermore, palpable tumor masses and synaptophysin expression are associated with a shorter cancer-specific survival.

Primary Primitive Neuroectodermal Tumor of the Urinary Tract

Primary primitive neuroectodermal tumor (PNET) of the urinary tract is a rare disease with aggressive behavior and poor prognosis. We analyzed 851 cases of urinary tract malignancies in our hospital between 1984 and 2004. Only three (0.035%) cases with PNET of the urinary tract were identified. Presenting symptoms included flank pain and hematuria. The first case was a 44-year-old man with left renal PNET who underwent hand-assisted laparoscopic radical nephrectomy and adjuvant chemotherapy. There was no recurrent tumor at the 4-year follow-up. The second case was a 75-year-old woman with right renal PNET with inferior vena cava (IVC) thrombosis extending to the right atrium. The patient underwent right radical nephroureterectomy and IVC thrombectomy with cardiopulmonary bypass. She died of metastatic disease 7 months later. The third case was a 45-year-old man with left ureteral PNET. Left ureteral segmental resection and partial cystectomy were performed. Tumor recurrence was noted 7 years later. The patient died of disseminated disease 1 year after the discovery of recurrence. Urinary tract PNET appears to be an aggressive malignancy. Long-term survival is possible if complete resection is performed at an early stage.

Primitive Neuroectodermal Tumor (PNET) of the kidney: a case report

Background

A case of Primitive Neuroectodermal Tumor (PNET) of the kidney in a 27-year-old woman is presented. Few cases are reported in the literature with a variable, nonspecific presentation and an aggressive behaviour. In our case, a radical nephrectomy with lymphadenectomy was performed and there was no residual or recurrent tumour at 24-month follow-up.

Methods

The surgical specimens were formalin-fixed and paraffin embedded. The sections were stained with routinary H&E. Immunohistochemistry was performed.

Results

The immunohistochemical evaluation revealed a diffuse CD99 positivity in the cytoplasm of the neoplastic cells. Pankeratin, cytokeratin AE1/AE3, vimentin, desmin, S100, cromogranin were negative. The clinical presentation and the macroscopic aspect, together with the histological pattern, the cytological characteristic and the cellular immunophenotype addressed the diagnosis towards primary PNET of kidney.

Conclusions

Since sometimes it is difficult to discriminate between PNET and Ewing's tumour, we reviewed the difficulties in differential diagnosis. These tumors have a common precursor but the stage of differentiation in which it is blocked is probably different. This could also explain their different biological behaviour and prognosis.