Imaging of non-central nervous system primitive neuroectodermal tumours: diagnostic features and correlation with outcome

The prognostic factors of Ewing sarcoma/peripheral primitive neuroectodermal tumor: A retrospective analysis of 67 patients at a single center

To investigate the characteristics and factors that impact the prognosis of Ewing sarcoma/peripheral primitive neuroectodermal tumor (ES/pPNET) patients. We retrospectively analyzed ES/pPNET patients diagnosed at our hospital from January 2011 to December 2020. We used 1-way analysis of variance to investigate whether the age differences between different subgroups were statistically significant and used the Kaplan-Meier method and Cox regression model for the survival analysis. Of the 67 included patients, 13 had central nervous system PNET, and 54 had ES/pPNET. The median survival time of the 54 ES/pPNET patients was 18 months; the 1-year, 3-year and 5-year progression-free survival rates were 37.0% and 9.3% and 1.9%, respectively; and the 1-year, 3-year and 5-year overall survival (OS) rates were 66.7%, 27.8%, and 7.4%, respectively. The 1-way analysis of variance results showed no statistically significant age difference between the different subgroups (P = .127 between the central nervous system PNET and ES/pPNET groups, P = .764 between different subgroups within the ES/pPNET group). The univariate survival analysis showed that metastasis at diagnosis and the treatment method were independent factors affecting the OS rate of ES/pPNET patient (P = .003 and 0.000, respectively). The multivariate survival analysis also showed that the treatment method and metastasis at diagnosis were related factors affecting OS (P = .025 and 0.001, respectively). The prognosis of patients with primitive neuroectodermal tumors is poor. The treatment method and metastasis at the time of diagnosis influences ES/pPNET patient survival time, but there is no significant tumor site-dependent correlation with patient age or sex.

Challenges of Diagnosing Primary Ewing's Sarcoma in the Small Intestine of the Elderly: A Case Report

Extraosseous Ewing's sarcoma (EES) is a malignant tumor that is classified as a rare disease. EES is common in children and adolescents, with a rarer incidence being present in the elderly. ES of the primary intestine is rare, with only a few reports described in the literature. Here we report a case of a 69-year-old male patient who was experiencing abdominal pain for over 3 months. Ultrasonography (US) revealed a solid hypoechoic lesion with multiple irregular necrotic areas in the left lower abdomen close to the dome of the bladder. Contrast-enhanced ultrasonography (CEUS) showed that the lesion exhibited heterogeneous enhancement and quick peripheral enhanced tissue wash-out classifying this mass as malignant. PET-CT showed a high metabolic mass in the lower abdomen, multiple metabolic nodules in the mesentery, considered as a small intestinal stromal tumor with lymph nodes metastasis, and that a diagnosis of lymphoma should be excluded. Esophagogastroduodenoscopy performed at another hospital 1 month prior to CT showed an abnormal density in the pelvic cavity that was considered as a colonic diverticulum with an abscess. The endoscopy showed no obvious occupying lesions. The mass was removed and postoperative pathology confirmed ES of the small intestine. The patient avoided receiving chemotherapy. After 2 months, skull metastasis was diagnosed and surgical intervention was done. His survival was only six months after the second surgery. To our knowledge, our case is the first report of ultrasound and CEUS manifestation of EES in the small intestine in elderly.

Extraskeletal Ewing sarcoma of the buccal space

Extraskeletal Ewing sarcoma (EES) is a rare soft tissue tumor, and EES of the head and neck is particularly rare. Radiographic imaging of these lesions is crucial given their anatomical complexity and infrequent incidence. Conventional EES imaging features include a large, hyperintense, heterogeneously enhancing lesion, with frequent invasion of local structures. In this case report, a 19-year old male presented with left facial swelling and pain. He underwent sclerotherapy and bleomycin treatment for a presumed lymphatic malformation. Initial imaging demonstrated a rim-enhancing lesion within the left buccal space with no muscle invasion or bony erosion present. Two years later, imaging identified an enlarging buccal mass with destruction of the zygomatic arch and inferolateral orbital wall. The patient underwent surgical resection of the mass. Pathology confirmed the mass to be a small round blue cell tumor and FISH testing confirmed the presence of the EWSR1 gene arrangement that is consistent with EES. The patient tolerated the procedure well and underwent chemoradiation therapy. At three years postoperatively, the patient remains disease free. The presented case demonstrates an unusual presentation of a buccal space EES as a rim-enhancing, centrally hypointense mass with no bony erosion or muscular invasion. The location and atypical imaging appearance of this case offer insight for future diagnosis of EES.

Update on Hereditary Renal Cancer and Imaging Implications

Up to 8% of renal cancers are thought to have a hereditary component. Several hereditary renal cancer syndromes have been identified over the last few decades. It is important for the radiologist to be aware of findings associated with hereditary renal cancer syndromes to detect tumors early, enroll patients in appropriate surveillance programs, and improve outcomes for the patient and affected family members. This review discusses from a radiologist's perspective well-known hereditary renal cancer syndromes and emerging genetic mutations associated with renal cancer that are less well characterized, focusing on imaging features and known associations.

A rare case of pelvic primitive neuroectodermal tumor with misleading symptoms: A case report

Peripheral Primitive NeuroEctodermal Tumors (pPNETs) are rare highly malignant tumors; originating from the neuroectoderm. Although PNETs may arise in various locations (most commonly in the extremities), very few cases have been reported in the pelvis. There is still poor evidence about the management of these tumors in the literature.

We present a rare case of pelvic PNET in a 20-year-old male. The patient presented with symptoms mimicking a lumbar disk hernia, which delayed the diagnosis. He was managed with a combination of a debulking procedure, adjuvant chemotherapy, radiotherapy; and has been in remission for 2 years upon follow-up.

This case highlights the importance of diagnosing such aggressive tumors as early as possible (as prognosis may vary significantly), and the challenge in the management of PNETs due to poor evidence.

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Primitive NeuroEctodermal Tumors (PNET) are highly malignant tumors that generally manifest in the extremities.

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Clinical symptoms are usually due to mass effect and depend on the site of presentation, but can sometimes be misleading.

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There is still poor evidence about the management of PNET in the existing literature.

Imaging findings of adrenal primitive neuroectodermal tumors: a series of seven cases

OBJECTIVE

To explore the imaging features of adrenal primitive neuroectodermal tumors (PNETs).

MATERIALS AND METHODS

This retrospective study included seven patients with surgically and pathologically confirmed adrenal PNETs. Among them, six underwent computed tomography (CT) scans, and one underwent magnetic resonance imaging. The imaging findings, including size, shape, margin, hemorrhage, calcification, cystic degeneration, regional lymph nodes involvement, tumor thrombus formation and enhancement pattern, were retrospectively analyzed.

RESULTS

Among the seven adrenal PNET patients, six were male, and one was female. The median age was 26 years (range 2-56 years). The disease generally presented with either insidious symptoms (n = 4) or non-specific symptoms, including right flank pain (n = 1) and left upper abdominal discomfort (n = 2). On the pre-enhanced CT images, the tumor usually appeared as a well-defined, rounded or oval, heterogeneous mass without calcification. Certain tissue characteristics, such as cystic degeneration (n = 5), capsule (n = 4) and hemorrhage (n = 2), were observed. Regional lymph node involvement was observed in three cases, and renal vein thrombus was observed in one case. All cases showed mild heterogeneous enhancement of the tumor on the enhanced CT images.

CONCLUSION

An adrenal PNET commonly presents as a relatively large, well-defined, heterogeneous mass with cystic degeneration, necrosis and a characteristic mild contrast-enhancement pattern on multiphase enhanced images. PNET should be considered when the diagnosis of common tumors is not favored by signs on images.

CLINICAL TRIAL REGISTRATION STATEMENT

This study was approved by the medical ethics committee of Xiangya Hospital, Central South University. The approval number is 201512538.

CT and clinical findings of peripheral primitive neuroectodermal tumour in children

OBJECTIVE

To describe the clinical, CT and pathological findings of paediatric peripheral primitive neuroectodermal tumours (pPNETs) to enhance the recognition of these rare tumours.

METHODS

The clinical, CT and pathological findings of 18 paediatric patients with pPNETs confirmed by biopsy or surgical pathology were retrospectively reviewed.

RESULTS

The age of these 18 paediatric patients with pPNETs ranged from 4 months to 15 years, with a mean age of 7.7 years. The lesions of these 18 paediatric patients with pPNETs were located in the head and neck (n = 4), chest (n = 2), abdomen and pelvic cavity (n = 6), spine (n = 3), ilium (n = 2) and femur (n = 1). Immunohistochemical examination revealed Homer-Wright rosettes in seven lesions, and 94.4% of lesions showed consistent positive staining for CD99. On plain CT images, the majority of pPNETs showed lesions that were ill-defined (72.2%), irregularly shaped (83.3%), heterogeneous (66.7%) or hypodense masses (94.4%), and together with osteolytic bone destruction when the lesion originated in the bone. Calcifications were found in three lesions. After contrast administration, all soft-tissue masses were persistently enhanced heterogeneously with various cystic or necrotic regions, and 71.4% of them had linear enhancement. 94.4% of soft-tissue masses showed a moderate degree of enhancement. Seven cases had lymph node metastasis at diagnosis.

CONCLUSION

Paediatric pPNET can involve any part of the body, and a large, ill-defined, aggressive soft-tissue mass and moderate heterogeneous enhancement with varying cystic regions and linear enhancement, with or without osteolytic bone destruction, on CT images could suggest the diagnosis.

ADVANCES IN KNOWLEDGE

Primitive neuroectodermal tumours constitute a rare type of malignant neuroectodermal tumours that have chromosomal translocations identical to Ewing's sarcoma, and reports about radiological characteristics of this disease in children are insufficient. This study has described the clinical features and CT and pathological findings in 18 paediatric patients diagnosed with pPNETs in different locations, as a way to enhance the recognition of these tumours and help to differentiate from other types of paediatric malignant bone and soft-tissue tumours.

Multiple Ewing Sarcoma/Primitive Neuroectodermal Tumors in the Mediastinum: A Case Report and Literature Review

Ewing sarcoma/primitive neuroectodermal tumors (ES/PNET) are high-grade malignant neoplasms. These malignancies present very rare tumors of thoracopulmonary area and even rarer in the mediastinum. In our knowledge, ES/PNET presented with multiple mediastinal masses has not been reported previously. We experienced a case of a 42-year-old man presented with gradual onset of left-side pleuritic chest pain. A contrast-enhanced chest computed tomography (CT) scan showed separate 2 large heterogeneously enhancing masses in each anterior and middle mediastinum of the left hemithorax. Positron emission tomography-computed tomography (PET-CT) scan revealed high fluorodeoxyglucose (FDG) uptake in the mediastinal masses. After surgical excision for the mediastinal masses, both of the masses were diagnosed as the ES/PNET group of tumors on the histopathologic examination. The patient refused postoperative adjuvant chemotherapy and came back with local tumor recurrence and distant metastasis on 4-month follow-up after surgical resection. We report this uncommon form of ES/PNET. We are to raise awareness that this rare malignancy should be considered as a differential diagnosis of the malignant mediastinal tumors and which can be manifested as multiple masses in a patient. Understanding this rare entity of extra-skeletal ES/PNET and characteristic imaging findings can help radiologists and clinicians to approach proper diagnosis and better management for this highly malignant tumor.

Peripheral primitive neuroectodermal tumor: dynamic CT, MRI and clinicopathological characteristics--analysis of 36 cases and review of the literature

Background

The peripheral primitive neuroectodermal tumor (pPNET) is a rare malignant tumor originating from neuroectoderm. The accurate diagnosis is essential for the treatment of pPNET.

Methods

we performed the largest cases of retrospective analysis thus far to review the unique computed tomography (CT), magnetic resonance imaging (MRI), and clinicopathological features of pPNET. The tumor location, morphological features, signal intensity, contrast enhancement characteristics, and involvement of local soft tissues of 36 pPNETs were assessed.

Results

Our results showed that there were more men (25/36) than women pPNETs patients. Unenhanced MRI (16 cases) showed that 14 cases were isointense and 2 cases were hypointense on T1WI. Nine cases were isointense and 7 were hyperintense on T2WI. Most pPNETs had heterogeneous signal intensity with small necrosis (CT: 31/36; MRI: 14/16) as well as heterogeneous enhancement (CT: 34/30; MRI: 15/16). The tumors usually had ill-defined borders and irregular shapes (CT: 30/36; MRI: 15/16). Pathologic exam showed small areas of necrosis in all tumors.

Conclusions

The diagnosis of pPNET should be suggested in young men when the imaging depicts a single large ill-defined solid mass with small area of necrosis, especially for those whose images show iso-intense on T1WI and T2WI and have heterogeneous enhancement.

Radiologic and clinicopathologic findings of peripheral primitive neuroectodermal tumors

BACKGROUND

Primitive neuroectodermal tumors (PNETs) constitute a rare type of malignant neuroectodermal tumors that have chromosomal translocations identical to Ewing's sarcoma (ES), and the characteristics of this disease remain unclear.

PURPOSE

To describe the clinical, radiological, and pathological features of peripheral PNETs (pPNETs) to enhance their recognition.

MATERIAL AND METHODS

The clinical, imaging, and pathologic findings of 35 patients with pPNETs were retrospectively reviewed, all being confirmed by biopsy or surgical pathology. All 35 patients had preoperative computed tomography (CT) examinations; 10 patients had preoperative magnetic resonance imaging (MRI) studies.

RESULTS

Of 35 pPNET patients, 54.3% had a primary tumor in soft tissue, the others in bone. On plain CT images, 33 lesions demonstrated heterogeneous hypodense masses with multiple lamellar lower density, and with osteolytic destruction if the tumor originated in bone. Calcification was only found in five lesions arising in soft tissue. All lesions enhanced heterogeneously with varying areas of cystic changes, and all lesions in bone and 52.6% of lesions in soft tissue showed ill-defined margins after contrast administration. On MRI, these tumors appeared in conjunction with osteolytic bone destruction and irregular soft tissue masses iso- to hypointense to skeletal muscle on T1-weighted images and showed heterogeneously high intensity on T2-weighted images. All lesions enhanced heterogeneously with cystic changes. Homer-Wright rosettes were observed in 15 lesions, and 97.1% lesions were positive for CD99 in histopathological results.

CONCLUSION

pPNETs can involve any part of the body, and a large, ill-defined, aggressive soft tissue mass and heterogeneous enhancement with or without osteolytic bone destruction on CT or MR images could suggest the diagnosis.

Radiological and clinical findings of osseous peripheral primitive neuroectodermal tumors

Peripheral primitive neuroectodermal tumor (pPNET) is a rare and highly malignant undifferentiated type of tumor. The aim of the present study was to analyze the computed tomography (CT), magnetic resonance imaging (MRI) and clinical findings of osseous pPNET. The present study retrospectively analyzed the clinical data and CT findings from 15 patients with osseous pPNET; the MRI findings from 11 of these 15 patients were confirmed by histopathological examination. The 15 patients included 9 men and 6 women. The mean patient age was 29 years (range, 16-64 years) and 11 cases were aged <30 years. A CT scan was performed in 15 cases and the findings included a lytic lesion (13 cases), a lytic lesion with irregular sclerosis and dilation (2 cases), a soft tissue mass (15 cases), calcification (2 cases) and periosteal reaction (5 cases). A total of 9 cases of soft tissue mass were heterogeneous, with different sizes of lower-density necrotic areas. An enhanced MRI scan was performed in 11 cases. On T1-weighted images (WI), the soft tissue mass was isointense (8 cases) and marginally hyperintense (3 cases). On T2WI, aggressive soft tissue masses were heterogeneous iso- or hyperintense (11 cases). On contrast-enhanced T1WI, marked heterogeneous enhancement was present in 10 cases and intermediate heterogeneous enhancement in 1 case. The results indicated that osseous pPNET mainly affects male adolescents and young adults. The CT findings of osseous pPNET were destructive lesions with a soft tissue mass and, occasionally, with periosteal reaction. The tumor was often isodense, with patchy hypodense areas. Tumor calcification was uncommon. The MRI findings were those of an aggressive soft tissue mass exhibiting isointensity on T1WI and iso- or hyperintensity on T2WI, with marked heterogeneous enhancement. Although the imaging characteristics of pPNETs may be non-specific, CT and MRI may be useful in delineating the extent of the tumor, identifying distant metastases, predicting resectability and monitoring treatment.

Rare presentation of peripheral primitive neuroectodermal tumor in the maxilla and mandible: A report of two cases

Peripheral primitive neuroectodermal tumor (pPNET) is a rare and highly malignant undifferentiated tumor, which presents in infants and young adults. pPNETs in the head and neck region are uncommon and have a varying incidence of occurrence. Peripheral PNETs of the maxilla and mandible are particularly rare. At present, only 16 cases of pPNET of the maxilla and 13 cases of pPNET of the mandible have been reported. The present study describes a case of pPNET of the maxilla in a 16-year-old male and a case of pPNET of the mandible in another 16-year-old male. The present study reports the radiological findings and the clinical courses of the two patients.

Multimodality imaging features, metastatic pattern and clinical outcome in adult extraskeletal Ewing sarcoma: experience in 26 patients

OBJECTIVE

To describe the multimodality imaging features, metastatic pattern and clinical outcome in adult extraskeletal Ewing sarcoma (EES).

METHODS

In this institutional review board-approved, health insurance portability and accountability act-compliant retrospective study, we included 26 patients (17 females and 9 males; mean age, 36 years; range, 18-85 years) with pathologically confirmed EES seen at our institute between 1999 and 2011, who had imaging of primary tumour. Imaging of primary tumour in all 26 patients and follow-up imaging in 23 was reviewed by two radiologists in consensus. Clinical data were extracted from electronic medical records.

RESULTS

The most common primary sites were the torso (n = 13), extremities (n = 10) and head and neck (HN) region (n = 3). The mean tumour size was 9 cm (range, 3-22 cm); tumours of the torso were larger than those of other areas (p > 0.05). Compared with the skeletal muscle, tumours were isodense on CT (21/21), hypointense (n = 5) to isointense (n = 14) on T1 weighted image, hyperintense on T2 weighted image (19/19) and were fluorine-18 fludeoxyglucose ((18)F-FDG)-avid [10/10; mean maximum standardized uptake value of 7 (range, 3-11)]. Necrosis (15/26), haemorrhage (5/26) and adjacent organ invasion (14/26) were present without calcification. Median follow-up was 16 months. 5 patients had local recurrence (torso, 3; extremity, 1; and HN, 1). Metastases developed in 11 patients (torso, 7; extremities, 3; and HN, 1; p > 0.05); 8 at presentation, most commonly to lung (9/11), peritoneum (4/11), muscles (4/11) and lymph nodes (4/11). Nine patients (torso, 7; extremity, 1; and HN, 1) died (10 months median survival) (p > 0.05).

CONCLUSION

Adult EESs are large tumours, which frequently invade adjacent organs and metastasize to the lung. EESs of the torso are larger, have more frequent metastases and poorer outcomes.

ADVANCES IN KNOWLEDGE

Adult EESs of the torso have poor outcomes compared with other EESs.

Clinical, pathological, and imaging characteristics of primitive neuroectodermal tumors of the spine

Primitive neuroectodermal tumors (PNETs) located in the spine are extremely rare, and information concerning these tumors in the medical literature is limited to single case reports. This pictorial essay presents the clinical, pathological, and imaging characteristics of PNET of the spine.

Imaging characteristics of primary spinal primitive neuroectodermal tumors. A report of five cases and literature review

Primary spinal primitive neuroectodermal tumors (PNETs) are rare and classified into peripheral and central types because the treatment strategy and outcome are different. This study describes five cases of primary spinal peripheral type PNETs. Magnetic resonance imaging showed large extradural masses in the cervical and thoracic spine with bony invasion and paraspinal extension in four cases and a transdural mass in the sacral spinal canal in one case. We also briefly summarize the imaging characteristics of 36 peripheral type and six central type primary spinal PNETs in the literature.

Radiological and clinicopathological features of pPNET

PURPOSE

To analyze the radiological and clinicopathological features of peripheral primitive neuroectodermal tumor (pPNET).

MATERIALS AND METHODS

We retrospectively reviewed the computed tomography (CT) and magnetic resonance (MR) imaging of 14 cases of pPNET confirmed immunohistochemically. Relevant clinical data was also obtained.

RESULTS

Of 14 cases, there were 10 male and 4 female with a mean age of 28 years. The main symptoms were the aggravated pain of the lesion site and enlarged palpable masses. Fourteen lesions were located in the chest wall (n = 4), retroperitoneum (n = 3), pelvic cavity (n = 2), intraspinal area (n = 2), nasal cavity (n = 1), leg ( n= 1) and iliac bone (n = 1). Eleven lesions originating from the soft tissue mainly demonstrated large and infiltrative mass with (n = 4) or without (n = 7) bony invasion. Ten cases of them showed heterogeneous density with patchy, necrotic foci and moderate heterogeneous enhancement. Four of them with large cystic area contained irregular septations within them. Two intraspinal cases had extradural lesions, extending through the intervertebral foramen and formed paraspinal soft tissue masses with vertebral destruction. The case within iliac bone demonstrated extensive mixed (lytic/osteoblastic) lesion with large adjacent soft tissue mass. After surgery or therapy, 10 patients died of local recurrences or metastases.

CONCLUSION

The diagnosis of pPNET should be suggested in young patient when imaging depicts a large, ill-defined, soft-tissue mass containing area of cystic degeneration with internal septations and extending along the neural route and nearby the middle of the trunk. The key for correct diagnosis is to inosculate imaging to clinical data.

A to Z of extraskeletal Ewing sarcoma family of tumors in adults: imaging features of primary disease, metastatic patterns, and treatment responses

OBJECTIVE

Though classically thought of as an osseous-based sarcoma of children and adolescents, it is important to recognize that approximately 20% of all cases of Ewing sarcoma family of tumors (ESFT) occur in patients older than 18 years, often with extraskeletal disease. Understanding the specific imaging features, manners of presentation, and patterns of behavior of ESFT is therefore important in all settings.

CONCLUSION

This article presents the imaging findings of ESFT in the adult, with specific attention to extraskeletal manifestations.

Primitive neuroectodermal tumor arising in the abdominopelvic region: CT features and pathology characteristics

BACKGROUND

We analyze the computed tomography (CT) findings of a peripheral primitive neuroectodermal tumor (pPNET) arising in the abdominopelvic cavity and to improve understanding of the CT images of the tumor.

MATERIALS AND METHODS

Twelve cases of pPNET confirmed by histopathology were analyzed retrospectively. Image characteristics of CT scanning were analyzed and compared with the pathology of the tumors.

RESULTS

There were 8 males and 4 females with mean age of 34.5 years. Unenhanced CT images showed large heterogeneous and ill-defined or well-defined masses with multiple patchy hypodense areas. The average diameter was 9.8 cm (range 4.0-17.2 cm). Contrast-enhanced CT images showed variable heterogeneous contrast enhancement with multiple non-enhancement areas. 3 cases revealed metastasis and 4 cases invaded into adjacent organs. Pathology showed areas of degeneration and necrosis in all tumors. Cluster of differentiation 99 and neurone specific enolase were detected positive in 11 and 12 cases, respectively.

CONCLUSIONS

In conclusion, pPNET in the abdominopelvic cavity likely affects young adults with a slight male preponderance and tend to be large and aggressive. Although CT findings are nonspecific and variable, a large ill-defined or well-defined heterogeneous mass with multiple patchy hypodense areas reflecting their cystic degeneration and necrosis on pathology examination may suggest the diagnosis of pPNET.

Imaging findings in mandibular primitive neuroectodermal tumour: a report of a rare case and review of the literature

Primitive neuroectodermal tumours (PNETs) are aggressive undifferentiated tumours that occur mainly in the central nervous system (CNS). Reviewing the literature, only six cases of primary PNET of the mandible have been reported. These rare tumours are usually overlooked in clinical practice. An 18-year-old woman who presented with dental caries and left cheek swelling was initially diagnosed with facial cellulitis, but the swelling persisted despite adequate intravenous antibiotic therapy. Subsequent ultrasound and MR examinations revealed a tumour originating from the left mandibular ramus. The ultrasonography-guided percutaneous core needle biopsy confirmed the diagnosis of peripheral PNET. The radiographic features of mandibular PNETs are similar to those of PNETs in other regions, except for haemorrhage, necrosis and calcification. In addition, this is the first reported case with sonographic and MR images of this rare tumour, and the first case that was diagnosed based on the ultrasonography-guided percutaneous core needle biopsy. Using these image characteristics, mandibular PNETs can be diagnosed more accurately.

Computed tomography and magnetic resonance imaging findings of peripheral primitive neuroectodermal tumors of the head and neck

PURPOSE

We aimed to analyze the computed tomography (CT) and magnetic resonance imaging (MRI) findings of peripheral primitive neuroectodermal tumor (pPNET) of the head and neck.

METHODS

Eight patients with pPNET of the head and neck confirmed by histopathological examination were analyzed retrospectively.

RESULTS

The average patient age was 8 years. The tumor location in the 8 patients was as follows: maxillofacial region (right, 2; left, 1), left maxillary sinus (1), right masticator space (1), left carotid space (1), right infratemporal fossa (1), and left parotid gland (1). All 5 patients who underwent CT demonstrated ill-defined soft masses and no calcification. Three patients with tumors in the maxillofacial region showed homogeneous small masses and a mild enhancement. The patient with left maxillary sinus tumor showed a heterogeneous mass with patchy, necrotic foci and mild heterogeneous enhancement. The patient with right masticator space tumor showed a heterogeneous mass, and marked heterogeneous enhancement. The T1-weighted images of the patients with right infratemporal fossa, left carotid space, and left parotid gland tumors were isointense. The T2-weighted images were heterogeneous and mildly hyperintense in 2 patients and hyperintense in 1 patient. Heterogeneous intermediate enhancement was demonstrated in 2 patients and mild ring enhancement in 1 patient.

CONCLUSION

The imaging features of pPNET of the head and neck are non-specific. An ill-defined, aggressive mass and variable enhancement on CT and MR images may suggest the diagnosis of pPNET. Peripheral PNET should be included in the differential diagnosis of children and adolescents' regional tumors.

Malignant pulmonary and mediastinal tumors in children: differential diagnoses

Conventional chest radiography is the most common imaging procedure in children. When a chest mass is discovered, cross-sectional imaging is often required to accurately localize and characterize the lesion in order to narrow the differential diagnosis. Knowledge of the differential diagnostic possibilities for chest tumors in children is important for both the pediatric and general radiologist because they differ from adults. The more common pediatric, malignant, mediastinal and pulmonary tumors and the characteristic imaging and clinical features that are useful in distinguishing between them are discussed in this review.

Case Report: Intracranial peripheral primitive neuroectodermal tumor - Ewing's sarcoma of dura with transcalvarial-subgaleal extension: An unusual radiological presentation

The occurrence of the intracranial, peripheral, primitive, neuroectodermal tumor, Ewing's sarcoma (pPNET-ES) of the dura, is very rare. Immunophenotypical as well as genetic analyses play key roles in its diagnosis and differentiation from central PNET. We describe here the CT scan and MRI findings of an interesting case of intracranial pPNET-ES arising from the anterior falx cerebri with a trancalvarial-subgaleal extension.

Imaging findings of abdominal peripheral primitive neuroectodermal tumor: report of four cases with pathological correlation

Peripheral primitive neuroectodermal tumors (peripheral PNETs) are rare in the abdomen. We report the imaging findings of four peripheral PNETs arising in the abdomen. Three were ill-demarcated tumors and one was a well-demarcated tumor, with extensive local invasion and lymph node metastasis in two cases, respectively. The tumors are of inhomogeneous attenuation and heterogeneous enhancement after intravenous administration of contrast materials. Although their imaging manifestations cannot distinguish them from other sarcomas, recognition of these imaging features may be helpful in suggesting the possibility of peripheral PNETs in some cases.

Imaging features of peripheral primitive neuroectodermal tumours

Primitive neuroectodermal tumours (PNETs) are a rare group of extremely aggressive small round cell tumours. Most commonly, they occur within the central nervous system. However, they also sporadically involve extracranial sites (peripheral PNETs). The chest wall is the most common of these sites, the imaging features of which have been well described in earlier studies. The present pictorial essay illustrates the imaging features of PNETs at various extracranial locations.

Desmoplastic small round cell tumor: imaging findings associated with clinicopathologic features

PURPOSE

To describe imaging findings of desmoplastic small round cell tumor (DSCRT) and to clarify the relation between radiologic appearances and clinicopathologic features.

MATERIALS AND METHODS

CT scans and MRI examinations of four male patients with histologically confirmed DSCRT (mean age = 20 years) were retrospectively analyzed.

RESULTS

The common imaging finding was multiple peritoneal masses with regular contour situated within mesentery. Tumors showed central low attenuation in 75% of patients on nonenhanced CT. All tumors showed inhomogeneous enhancement on CT. Small foci of punctate calcification were identified in a part of the tumor in all patients. Bone metastases were identified on enhanced CT in two patients 2 and 8 months after diagnosis, respectively. Pleural dissemination was identified in all patients, and one patient had double-sided dissemination. T2-weighted MRI showed inhomogeneous high signal intensity, and small cysts were identified in two patients. Fluid-fluid levels were identified in six tumors on T2-weighted images, which suggested the presence of hemorrhage. Tumors had inhomogeneous signal intensity low or isointense relative to skeletal muscle on T1-weighted images. Two lesions exhibited inhomogeneous enhancement with central low intensity consistent with necrosis.

CONCLUSION

Imaging studies can depict disseminated characteristics and disease extent during the clinical course of DSRCT.