Primary primitive neuroectodermal tumour of the parotid gland

Parotid Ewing's sarcoma: Extra-skeletal uncommon condition

Introduction

The parotid gland is a very rare location of Ewing's sarcoma. Its clinical and radiological manifestations are atypical. Its management is based on a multidisciplinary approach to improve prognosis and survival.

Discussion

The diagnosis of parotid Ewing's sarcoma is determined by a combination of genetic and histological criteria. Its local aggressiveness and high metastatic potential require prompt and appropriate management. Many prognostic features affect its management, the most important is the TNM staging.

Conclusion

Limited cases of parotid Ewing's sarcoma have been published in the literature. This small number of reported cases is the only way to study its characteristics.

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The parotid gland is a very rare location of Ewing's sarcoma.

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The diagnosis of parotid Ewing's sarcoma is determined by a combination of genetic and histological criteria.

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Many prognosis features affect its management, the most important is the TNM staging.

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.

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.

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.

Primitive neuroectodermal tumor (PNET) of the uterus in a renal allograft patient: a case report

The incidence of malignancy after renal transplant has been reported to range from 4% to 18%. Tumors of the skin and lip tend to be the most common with non-Hodgkin lymphoma comprising 20% of all neoplasms. Primitive neuroectodermal tumors (PNET) are collectively described as being a part of the Ewing sarcoma family of tumors. PNET occur more commonly in the second decade of life, predominantly affecting Whites and Hispanics, and rarely occur in individuals of African or Asian descent. The most common primary site of involvement is along the central axis, particularly the chest (Askin tumor), but it can arise in any soft tissue. PNET also occur in the head and neck. PNET involving the cervix, urinary bladder, uterus, and vagina have been reported. We describe a case of a 15-year-old female who, 9 years after receiving a living related renal transplant, developed a post-transplant PNET of the uterus.

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).

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.

Malignant peripheral primitive neuroectodermal tumor-peripheral neuroepithelioma of the head and neck: a clinicopathologic study of five cases and review of the literature

BACKGROUND

The term primitive neuroectodermal tumor (PNET) encompasses a number of neoplasms of common neuroectodermal origin, but of variable clinical, histopathologic, ultrastructural, and molecular characteristics. Here, we focus on one particular member of the PNET family, the malignant peripheral PNET (pPNET) or peripheral neuroepithelioma of head and neck.

METHODS

Five patients diagnosed with malignant pPNET-peripheral neuroepithelioma of head and neck were included in the study. All existing literature was reviewed.

RESULTS

The diagnosis of malignant pPNET-peripheral neuroepithelioma of the head and neck was confirmed in all five cases. All patients are alive after treatment with a combination of therapeutic modalities; only one patient had metastatic disease develop. A literature review revealed another 38 reported cases.

CONCLUSIONS

Malignant pPNET-peripheral neuroepithelioma should be included in the differential diagnosis of small, round, blue cell tumors of head and neck. A combination of multiple diagnostic modalities is essential for correct diagnosis, and multimodality treatment offers the best outcome.

Primitive neuroectodermal tumors of the pancreas: a report of seven cases of a rare neoplasm

Primitive neuroectodermal tumors (PNETs) have rarely been described in solid organs. We report a series of seven PNETs of the pancreas. The clinical, gross, microscopic, and immunohistochemical features of these seven PNETs of the pancreas are described, as are the genetic analyses in five cases. The patients ranged in age from 6 to 25 years (mean 18 years). Four of the patients were male. All of the patients presented with jaundice and/or abdominal pain. All of the tumors were located in the head of the pancreas, and they ranged in size from 3.5 to 9.0 cm. Light microscopy revealed the typical morphologic features of PNETs. By immunohistochemistry the neoplastic cells in all seven cases expressed O13 (CD99, p30/32MIC2). In five of six tested cases, the neoplastic cells also expressed cytokeratin. All of the tumors expressed neural-neuroendocrine markers. Two of the three cases examined ultrastructurally showed prominent epithelial features. There was cytogenetic or molecular genetic evidence of the t(11;22)(q24;q12) in four of five cases examined. Clinical follow-up was available in five cases. Two of the patients were alive with no evidence of disease at 33 and 43 months. One patient was alive with disease at 27 months. One patient died of postoperative complications. Another patient died of disease 4 years after diagnosis. PNET can sometimes arise as a primary neoplasm of the pancreas. Like PNETs arising in more conventional sites, pancreatic PNETs occur in the pediatric and adolescent population, show the characteristic staining with O13, and typically harbor the t(11;22)(q24;q12) chromosomal translocation. PNETs should be included in the differential diagnosis of poorly differentiated small round cell tumors of the pancreas. Moreover, they should not be confused with pancreatic endocrine tumors, which also demonstrate dual epithelial and neuroendocrine differentiation by immunohistochemistry and express O13 in 30% of cases.

Imaging of peripheral PNET: common and uncommon locations

AIM

We present the imaging features of peripheral primitive neuroectodermal tumour (PNET) in eight children, highlighting the unusual locations of this tumour in three children.

MATERIALS AND METHODS

At presentation, the tumours were studied with magnetic resonance imaging (MRI; n = 6), computed tomography (CT; n = 7) and ultrasound (US; n = 1). The diagnoses were confirmed histologically (n = 8), immunohistochemically (n = 8), by cytogenetics (n = 3) and electron microscopy (n = 1). Correlation with gross pathology, histology, treatment and outcome were obtained.

RESULTS

The tumours were located in the chest wall (n = 2), shoulder, pelvis, small bowel mesentery, adrenal gland, dura mater and skin and subcutaneous tissue of the abdominal wall (n = 1 each). Peripheral PNET arising from the small bowel mesentery, adrenal gland and dura mater have not been previously reported in the English literature. The tumours were mainly large (mean size: 10.6 cm) and infiltrative. All tumours were heterogeneously hyperintense on T2-weighted MRI, heterogeneously iso/hypodense on CT and had variable contrast enhancement. Most tumours were heterogeneously hypointense to muscle on T1-weighted MRI. US showed a hypoechoic mass with a cystic component.

CONCLUSION

Peripheral PNET can occur in unusual locations. The clinical and imaging features of peripheral PNET are non-specific, making tissue diagnosis essential. PNET should be included in the differential diagnosis of aggressive soft tissue tumours in children.

Peripheral primitive neuroectodermal tumor of the small bowel mesentery: a case showing perforation at onset

A case of peripheral primitive neuroectodermal tumor of the small bowel mesentery with an uncommon clinical onset is reported. A 40-year-old man was admitted to hospital because of acute severe abdominal pain. Chest X-ray revealed a free air sign beneath the diaphragm. At emergency surgery a mass measuring 11.0 x 8.0 cm with perforation was located in the jejunal mesenteric region. Histologically the resected lesion consisted of sheets of undifferentiated small round cells forming abortive Homer Wright rosettes. Some spindle-shaped cells showed perivascular pseudorosettes. Immunohistochemical study revealed that the tumor cells expressed positivity against CD99 (MIC2), neuron-specific enolase, synaptophysin and vimentin. To the authors' knowledge this is the first documentation of peripheral primitive neuroectodermal tumor of the small bowel mesentery with perforation at onset.