Primitive neuroectodermal tumor of the lung

Operative treatment of pulmonary primitive neuroectodermal tumor: a case report and literature review

BACKGROUND

Pulmonary primitive neuroectodermal tumor (PNET), a member of the Ewing sarcoma family of tumors, is a rare malignancy that is associated with a grim prognosis. To date, fewer than 30 cases of pulmonary PNET have been reported. In this case report, we present the clinical details of a 12-year-old girl with pulmonary PNET who underwent surgical treatment. We also conducted an analysis and summary of other relevant studies and the surgical outcomes.

CASE PRESENTATION

In May 2018, a 12-year-old girl was admitted with symptoms of cough and blood-tinged phlegm. A computed tomography scan revealed a large mass, measuring 12.9 cm × 8.1 cm, in the right middle and lower lungs. A percutaneous lung biopsy confirmed poorly differentiated tumor cells with a nested growth pattern. Immunohistochemical staining demonstrated positive expression of CD99, CD56, Vimentin, and Synaptophysin. The patient was diagnosed with pulmonary PNET. Following three cycles of neoadjuvant chemotherapy, a substantial reduction in tumor volume was observed. Subsequently, the patient underwent a surgical procedure involving pneumonectomy and partial resection of the left atrium with the assistance of cardiopulmonary bypass. The patient was discharged 37 days after surgery. During a three-year follow-up period, she exhibited no signs of tumor recurrence and has successfully returned to school.

CONCLUSIONS

This case highlights the successful management of an advanced PNET with neoadjuvant chemotherapy, pneumonectomy, and partial resection of the left atrium employing cardiopulmonary bypass. The patient remained disease-free after three years. Our analysis of surgically treated cases indicates that neoadjuvant chemotherapy can contribute to improved prognoses for PNET patients. It is crucial to emphasize that complete surgical excision remains the cornerstone of treatment, underscoring the importance of surgeons considering radical surgical approaches whenever feasible for patients with pulmonary PNETs.

Rare Primary Pulmonary Primitive Neuroectodermal Tumor: A Case Report and Literature Review

Primitive neuroectodermal tumors (PNETs) arising from the lung without thoracic wall involvement are extremely rare and particularly aggressive neoplasms. Herein, we present the case of a 41-year-old woman with pulmonary PNET diagnosed following histopathological, immunohistochemical, and molecular pathological examination of a surgical biopsy specimen. The case report is accompanied by a literature review of primary pulmonary PNETs.

Primary pulmonary Ewing sarcoma/peripheral primitive neuroectodermal tumor

Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) is a malignant small round cell sarcoma commonly occurring among children, adolescents, and adults. We report a rare case of ES/pPNET arising from the lung in a 49-year-old woman. She was found to have a mass in the right lung on a screening imaging study for her BRCA2 mutation. A lobectomy was performed and the mass had histological, immunohistochemical, and molecular features of ES/pPNET. Few cases of primary pulmonary Ewing sarcoma have been reported.

Primary bronchial Ewing sarcoma

INTRODUCTION

Primary bronchial Ewing sarcoma (ES) is a rare endobronchial tumor.

PRESENTATION OF CASE

A 65-year-old male presented with six-month history of progressive shortness of breath. Flexible bronchoscopy showed an endobronchial polypoid tumor in the left main stem bronchus about 2 cm from the carina. The tumor was resected by a left bronchial sleeve resection using a right postero-lateral thoracotomy approach. Pathology showed complete tumor resection with negative margins. The morphological and immune-phenotypical features of the resected specimen were compatible with ES. He had an uneventful post-operative recovery. He did not receive adjuvant radiation or chemotherapy and remains disease free at 9 months follow up.

DISCUSSION

A review of the literature identified six other cases of primary bronchial ES. In addition, there were three reported cases of primary ES involving the trachea and thirteen involving the lung parenchyma. Bronchial ES appeared to have a relatively better prognosis than ES involving the trachea or the lung. Our case demonstrates that primary bronchial ES may be treated safely with limited resection, lung preservation and without the need for adjuvant therapy if negative margins can be achieved.

CONCLUSION

Sleeve resection without adjuvant therapy may be a safe treatment option for primary bronchial ES.

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.

Benefit of Sunitinib in the treatment of pulmonary primitive neuroectodermal tumors: a case report and literature review

Primitive neuroectodermal tumor (PNET) is a highly aggressive small round celltumor but is extremely rare in the lung. Next-generation sequencing (NGS) has led to breakthroughs for genetic analyses and personalizedmedicine approaches for cancer treatment.We report the case of a 30-year-old woman with an advanced pulmonary PNET treated with multiple chemotherapeutic regimens, and achieved a partial response (PR) as a best response. However, there was a disease progression after these treatment regimens.The NGS revealed the presence of a copy number loss (CNL) of Von Hippel-Lindau (VHL), CDKN2A/B and TP53 genes. The specific VHL CNL has not previously been associated with PNET, but has been reported in other tumors and has been associated with response to Sunitinib. Sunitinibwas then instituted for this patient and resulted in PR after the failure of multiple chemotherapeutic regimens. To our knowledge, this is the first report of pulmonary PNET with CNL of VHL gene that benefits from Sunitinib treatment. This case illustrates the potential of clinicalNGS to open unexpected avenues for treatment and thereby improve patient outcomes.

Late onset of primary pulmonary primitive neuroectodermal tumor: a case report

Lungs are one of most metastatic areas for primitive neuroectodermal tumor (PNET), however primary pulmonary PNET is extremely rare. Here we present a case of a 58-year-old male patient with a tumor in the right lung that originated from the lung but not from chest wall. Patient was diagnosed with PNET following histological and immunohistochemical examination of CT-guided percutaneous tru-cut needle biopsy and no distant metastasis were detected in PET-CT scan. As advised recently in published literature, surgical resection following neoadjuvant chemotherapy protocol is preferred in the treatment of our patient as it has better success of complete resection leading to higher 5-year survival rates. Although primary pulmonary PNET is uncommon, it should be taken into account and complete surgical resection should be aimed as treatment to achieve higher survival rates.

Primitive Neuroectodermal Neoplasia in Coho Salmon, Oncorhynchus kisutch

Twelve coho salmon, approximately 8 weeks old, were each observed to have a single neoplasm involving the dorsolateral axial skeletal musculature. The neoplasm was closely associated with the vertebrae in all cases. The neoplasm was composed of islands containing small cells with round and occasional spindeloid morphology. Neoplastic cells had basophilic cytoplasm and vesicular nuclei. These cells exhibited immunopositivity only for vimentin and S-100 protein. Ultrastructurally, neoplastic cells had nuclei with a predominance of euchromatin, cytoplasm containing marked amounts of rough endoplasmic reticulum, scant amounts of smooth endoplasmic reticulum, and scattered mitochondria. Rudimentary cell junctions were occasionally observed between adjacent neoplastic cells. Based on the close association of these neoplasms with the vertebrae as well as the histologic, ultrastructural, and immunohistochemical findings, these neoplasms were considered to all be primitive neuroectodermal neoplasms.

Premitive neuro-ectodermal tumour of the lung

Primitive neuro-ectodermal tumour of the lung is an extremely rare occurrence and we hereby report a case of a neuro-ectodermal tumour of the lung which was proved by immuno-histochemical examination of the resected specimen, and he had a very aggressive pattern of behavior.

Endobronchial Primitive Neuroectodermal Tumor With Pneumothorax Ex Vacuo

We experienced a rare case of an endobronchial primitive neuroectodermal tumor of the left main bronchus. Initially we suspected pneumothorax caused by a collapsed left upper lobe and an air-entrapped lower lobe. After tube thoracostomy, the pneumothorax persisted without air leakage. A tumor was detected at the left main bronchus on computed tomography and bronchoscopy, and diagnosed pathologically as small cell lung cancer. Under the presumed diagnosis of limited-stage small cell lung cancer, we performed a left pneumonectomy. The tumor was eventually identified pathologically as a primitive neuroectodermal tumor. Although adjuvant chemoradiotherapy was not performed, no recurrence was observed.

Primary Multiple Pulmonary Primitive Neuroectodermal Tumor: Case Report and Literature Review

Primitive neuroectodermal tumors (PNETs) arising directly from the lung are extremely rare but particularly aggressive neoplasms. Although thoracic PNET usually develops on the chest wall, there have been reports of primary Ewing sarcoma/PNET of the lung.We present the case of a 16-year-old male with PNET diagnosed following histologic and immunohistochemical examination of a video-assisted thoracic surgical biopsy. As typically occurring for these tumors, the diagnosis was initially delayed in our patient and prognosis was poor despite aggressive surgical resection and postoperative chemotherapy. We attempted to explore the use of targeted pharmacotherapy through high-throughput sequencing in this case. We found that this treatment using Avastin and Cetuximab could provide a new therapeutic direction for PNET.PNENTs arising from the lung parenchyma without pleural or chest wall involvement are extremely rare. Although uncommon, if the pathological features are similar to Ewing sarcoma, PNENTs should be kept in mind, and the target therapy may be a potent treatment for this disease.

Primary ewings sarcoma of the lung

Extraosseous ewings sarcoma is an extremely rare neuroectodermal tumour. We report the case of a 30-year-old female who presented with right sided pulmonary mass. Radiology, histopathology and immunohistochemistry confirmed the diagnosis of primary pulmonary Ewings sarcoma. This case highlights the fact that Ewings sarcoma should be considered in differential diagnosis of patients presenting with pulmonary mass.

Primitive neuroectodermal tumor (PNET) of the lung in an adult woman

Primary primitive neuroectodermal tumors (PNETs) are extremely rare in the lung and especially in adult women. We describe a case of PNET of the lung with aggressive behavior in 31-year-old woman. Diagnosis was based on histopathological and immunohistochemical studies, and confirmed by molecular genetic analysis of chromosome rearrangements in the EWSR1 gene region. Clinical follow-up, post-mortem findings, and differential diagnosis are also discussed.

Thoracic primitive neuroectodermal tumor: an unusual case and literature review

We describe herein a rare case of a primary primitive neuroectodermal tumor (PNET) in the mediastinum of a 75-year-old man. Grossly, the tumor was located in the left upper anterior mediastinum. Transcutaneous fine-needle biopsy (TCNB) revealed small round-cell proliferation. The expression immunohistochemical analysis was confirmed the diagnosis of PNET. He was successfully treated with chemotherapy and is alive with no sign of recurrence for 17 months after the diagnosis.

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.

[A peripheral primary neuroectodermal tumour of the lung in a man of 49 years]

Peripheral primary neuroectodermal tumours (pPNET) of the lung are very rare malignant tumours. The authors report a case of pPNET of the lung in a 49-year-old man, who developed a sarcoma in the irradiated territory 7 years after completion of adjuvant radiotherapy. A review of the literature on pPNET of the lung is presented in the light of this case report.

Ewing's sarcoma family of tumors originating in the main bronchus

Ewing's sarcoma family tumors (ESFT), which include Ewing's sarcoma and primitive neuroectodermal tumors (PNET), have been reported to originate in a variety of sites, mostly in the extremities. Previous reports have shown ESFT originating in the thoracic region, such as chest wall and peripheral lung. We herein report the first case of the ESFT that originated in the main bronchus. Endobronchial snare resection was followed by five courses of chemotherapy (VDC-IE; including vincristine, doxorubicin, cyclophosphamide, ifosfamide and etoposide) and sequential radiation. After the treatment, the patient's condition has improved, and he has remained disease-free for the past year.

Primary pulmonary primitive neuroectodermal tumor (PNET): a clinicopathological and immunohistochemical study of six cases

BACKGROUND

The clinicopathological and immunohistochemical features of six primary pulmonary primitive neuroectodermal tumors (PNETs) are reported.

METHODS

The patients were four men and two women aged 22-56 years (mean = 32.3 years). The main presenting symptoms included chest pain, shortness of breath, and cough. The tumor size ranged from 4 to 9.6 cm.

RESULTS

Macroscopically, the tumors were circumscribed, yellow-white in color, and of soft and friable consistency. Histologically, the lesions were composed of a monomorphic population of solidly packed round cells with a round-to-ovoid nucleus, fine chromatin, small nucleoli, and scanty pale cytoplasm. Immunohistochemically, the tumor cells were uniformly positive for CD99, neuron-specific enolase, and vimentin, and single cases focally expressed cytokeratin and S100. Fluorescence in situ hybridization analysis performed in two cases showed positive rearrangement for the EWSR1 gene at the 22q12 locus. Follow-up information available for four patients showed that three had died 24-54 months after diagnosis and one patient is alive 11 months after diagnosis. Two patients were lost to follow-up.

CONCLUSION

Primary PNETs of the lung are rare tumors that need to be added to the differential diagnosis of primary pulmonary neoplasms composed of small cells. Awareness of this entity as a primary pulmonary neoplasm is required in order to avoid misdiagnosis and unsuitable treatment of patients.

[Pulmonary Ewing sarcoma/primitive neuroectodermal tumor: a case report and a review of the literature]

Primary thoracic sarcomas are very rare. The most common intrathoracic variants are synovial sarcoma, angiosarcoma, leiomyosarcoma, rhabdomyosarcoma, and sarcomatoid mesothelioma. Although thoracic Ewing sarcoma/primitive neuroectodermal tumor (PNET) usually develops on the chest wall, there have been reports of primary Ewing sarcoma/PNET of the lung. We present the case of a 22-year-old woman with Ewing sarcoma/PNET diagnosed following histologic, immunohistochemical, and in situ hybridization studies of a bronchial biopsy specimen. Radiography, ventilation-perfusion scintigraphy, and a bone marrow biopsy confirmed that the tumor was not metastatic. The patient was started on a chemotherapy regimen of vincristine, actinomycin, cyclophosphamide, doxorubicin, ifosfamide, and etoposide and responded well. She is now being seen regularly at our outpatient clinic.

Surgical treatment and prognosis of primitive neuroectodermal tumors of the thorax

INTRODUCTION

Primitive neuroectodermal tumors (PNETs) are rare, rapidly progressive, small- round cell tumors with a poor prognosis despite multimodal therapy, including surgery and chemoradiotherapy. The treatment of choice was unknown since no clinical series with surgical therapy had been reported. We evaluated the impact of multimodal treatment in patients with PNETs located in the thoracic region.

METHODS

Between 1998 and 2006, 25 patients with PNETs in the thoracic region were treated in 3 tertiary-care hospitals. The patients consisted of 15 males and 10 females with a mean age of 27.2 years (range, 6-60). The tumor was in the chest wall in 20 (involving the costovertebral junction in 9), the lung in four, and the heart in one patient. Twelve patients received neoadjuvant chemotherapy (54.5%), and 22 of 25 patients underwent surgery.

RESULTS

In patients who received neoadjuvant treatment, the mean regression rate was 65.4% (range, 30-100%). Eighteen (82%) patients underwent chest wall resection, while 7 (32%) had vertebral resections, and the remaining 4 (16%) had pulmonary resections. A complete resection was possible in 18 of 22 patients (82%). Patients with incomplete and complete resections had 25% and 56% 5-year survival rates, respectively (p = 0.13). The progression-free 3-year survival rate was 36% and the median survival time was 13 months. The complete resection rate was significantly higher in patients receiving neoadjuvant therapy (p = 0.027). The 5-year survival rate of the patients with or without neoadjuvant therapy was 77% and 37%, respectively (p = 0.22) although it prolonged the disease-free survival (p = 0.01). The 5-year survival rate of patients without costovertebral junction involvement was 66%, whereas patients with PNETs involving the costovertebral junction had a 21% 3-year survival. The difference was statistically significant (p = 0.01). The 5-year progression-free survival rate of patients without costovertebral junction involvement was 58%, whereas patients with PNETs involving the costovertebral junction had a 14% 1-year progression-free survival (p = 0.004).

CONCLUSIONS

PNET is an aggressive malignancy that often requires multimodal therapy. Induction chemotherapy leads to a greater complete resection rate and better disease-free survival, while involvement of the costovertebral junction indicates a poorer survival.

Primary pulmonary Ewing's sarcoma/primitive neuroectodermal tumor in a 67-year-old man

Extraskeletal Ewing's sarcoma (EES) is a branch of neuroectodermal tumor (PNET), which is very rare soft tissue sarcoma. We report a case of EES/PNET arising is the lung of a 67-yr-old man. Computed tomography, bone scintigraphy, and positron emission tomography confirmed the mass to have a primary pulmonary origin. The mass showed positive reactivity in the Periodic Acid Schiff (PAS) stain and MIC-2 immunoreactivity in immunohistochemical stain. Fluorescence in situ hybridization (FISH) was performed, which revealed an EWSR1 (Ewing sarcoma breakpoint region 1) 22q12 rearrangement. The diagnosis was confirmed both pathologically and genetically. The mass lesion was resected, and the patient is currently undergoing chemotherapy.

Primary pulmonary primitive neuroectodermal tumor: CT and skeletal scintigraphic image features with pathologic correlation (2006: 6b)

We describe a rare case of a primitive neuroectodermal tumor (PNET) originating in the lung of a 28-year-old woman. A lung mass was detected incidentally on a chest radiograph taken before a Caesarian delivery. The chest P-A view showed a well-defined, lobulated mass in the right lower lobe with a small pleural effusion on the right. A thoracic CT with contrast enhancement showed a lobulated, heterogeneous, enhanced mass of approximately 9.2 x 8.4 x 6.3 cm with inner amorphous calcifications in the right lower lobe and a small right pleural effusion. A right lower lobectomy was performed 1 month after delivery. The pathology report was a primary pulmonary PNET with focal visceral pleural involvement.

Mouth metastasis of peripheral primitive neuroectodermal tumor

We describe a case of oral metastasis of peripheral primitive neuroectodermal tumor (pPNET) in a 68-year-old man, who presented the primary lesion in the chest. Oral metastasis of pPNETs is very rare and we have not found any similar case reported in the English literature. Clinical examination showed an extensive and ulcerated fleshy mass measuring 3.0 x 3.5 cm in the right lower gingivae. Microscopic examination showed sheets of proliferating small, hyperchromatic, round cells. Tumor cells were reactive to neuron-specific enolase (NSE), vimentin and MIC-2 gene by immunohistochemistry, consistent with PNET. The patient died 3 weeks later because of respiratory insufficiency.

Primary poorly differentiated monophasic synovial sarcoma of the lung. A case report with immunohistochemical and genetic studies

We describe a case of a poorly differentiated monophasic synovial sarcoma arising in the lung of a 50-year-old man. The tumor, which was located in the right upper lobe, was lobulated, relatively well-circumscribed, and whitish to yellowish in color. Microscopically, it was composed exclusively of ovoid to polygonal or short spindle cells, with a high nuclear to cytoplasmic ratio and relatively scant cytoplasm, arranged in solid sheets or in a hemangiopericytomatous pattern with intervening wiry collagen fibers. At the periphery of the tumor, entrapped benign alveolar epithelium produced a pseudo-biphasic appearance. In some areas, an abundance of keloidal collagen imparted a close resemblance to a solitary fibrous tumor, making it difficult to establish the diagnosis on the initial needle biopsy, although the malignant nature of the tumor was suggested because of nuclear anaplasia. Immunohistochemically, the tumor was positive for cytokeratin AE1/AE3, CAM5.2, EMA, vimentin, bcl-2 protein, calretinin, and CD34. The reverse transcriptase-polymerase chain reaction (RT-PCR), using RNA extracted from fresh-frozen tissue, demonstrated SYT/SSX-1 fusion transcripts, confirming the diagnosis of synovial sarcoma. Microscopic examination demonstrated metastatic deposits in hilar lymph nodes. This case indicates that a primary pulmonary synovial sarcoma, particularly in its poorly differentiated form, is a diagnostically challenging and highly aggressive neoplasm typically found at an advanced stage.

Ectopic neural and neuroendocrine neoplasms

Although neural and neuroendocrine tissues are distributed virtually ubiquitously throughout the body, the occurrence of selected neoplasms related to those lineages is extremely uncommon in some topographic sites. This review considers the clinicopathologic characteristics of heterotopic pituitary adenomas; neuroendocrine carcinomas in non-organ-based locations; ectopic (extraneuraxial) meningiomas and gliomas; visceral neuroblastic neoplasms and primitive neuroectodermal tumors; and paragangliomas arising outside the sympathoadrenal neural network. Practical approaches to differential diagnosis are emphasized.

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.