A Clinicopathological and Molecular Analysis of Sellar/Suprasellar Neurocytoma Mimicking Pituitary Adenoma

OBJECTIVE

To investigate the clinicopathological characteristics, molecular genetic characteristics and prognosis of extraventricular neurocytoma located in the sellar/suprasellar region.

METHODS

Seven archived tumor samples derived from 4 patients with neurocytoma in the sellar/suprasellar region were collected from the First Affiliated Hospital of Fujian Medical University and the Affiliated Hospital of Qingdao University and retrospectively analyzed for clinical manifestations, imaging features, and histopathological features. Neuronal and pituitary biomarkers and molecular features were detected in these tumor tissues by immunohistochemistry and FISH or Sanger sequencing. The related literature was reviewed.

RESULTS

Three patients were female, while 1 was male, with an average age of 35.5 years (range: 27 to 45 years). The initial manifestations were mainly headache and blurred vision in both eyes. The first MRI examination showed marginally enhancing masses in the intrasellar or intra- to suprasellar region. The diagnosis of pituitary adenomas was based on imaging features. The levels of pituitary hormones were normal. Histologically, the tumor cells were arranged in a sheet-like, monotonous architecture and were uniform in size and shape with round to oval, exquisite and hyperchromatic nuclei, which densely packed close to one another and were separated only by a delicate neuropil background. There was no evident mitosis, necrosis or microvascular proliferation. The three cases of recurrent tumors were highly cellular and showed increased mitotic activity. Immunohistochemically, the tumor cells were positive for syn, CR, CgA, and vasopressin and were focally positive for NeuN, TTF-1, NF, CK8, vimentin, and S100 proteins. Other markers, including IDH1, BRAF VE1, Olig-2, and EMA, were negative. Pituitary transcription factors and anterior pituitary hormones were negative. Molecular genetic testing showed that the tumor cells lacked IDH gene mutations, LOH of 1p/19q, MYCN amplification, and EGFR alteration. With a median follow-up of 74.5 months (range 23 to 137 months), 3 patients relapsed at 11, 50, and 118 months after the initial surgery.

CONCLUSION

The morphological features and immunophenotypes of neurocytoma in the sellar/suprasellar region are similar to those of classic central neurocytoma. The prognosis is relatively good. Gross-subtotal resection and atypical subtype may be related to tumor recurrence.

Extraventricular neurocytomas: a systematic review of the literature in the pediatric population

Extraventricular neurocytomas (EVNs) are rare neuroepithelial neoplasms of the central nervous system that were first described in 1997. Most studies in patients with EVNs have incorporated mixed age groups. The tumor's clinical behavior specifically in children has not been explored in depth, while a detailed statistical analysis has never been performed in this age group. Hence, we performed a systematic review to address possible prognostic factors and the appropriate management in children with EVNs. Relevant studies were identified by searching the MEDLINE and SCOPUS databases. We included studies concerning patients 18 years of age or younger who were histologically diagnosed with EVNs. A total of 52 studies with 79 patients were included. The mean age of the patients was ~ 10 years with a male predilection (~ 2:1). Most of these tumors were located in the frontal (49%) lobe. We observed that gross total resection of the tumor was significantly lower in cases of atypical EVNs (p < 0.05). Additionally, atypical EVNs were associated with worse overall survival compared to typical EVNs (p = 0.05). Children 4 years of age or under had a worst outcome (p = 0.001). The patient's sex and the extent of the tumor's resection did not appear to affect the prognosis in a statistically significant manner. Contrary to the results of previous studies, the use of adjuvant radiotherapy or chemotherapy for the treatment of EVNs was not associated with better outcomes in the pediatric population. Thus, a less aggressive management of children with EVNs compared to the adult population is suggested.

Hypothalamic hormone-producing tumors

The hypothalamus is functional neuroendocrine tissue that is responsible for the synthesis and secretion of peptide hormones that regulate the pituitary and other endocrine functions. Endocrine tumors of the hypothalamus are rare but they provide a model for tumors that have both structural and functional effects. Patients with hypothalamic endocrine tumors suffer mass effects including headaches, visual disturbances, and endocrine dysfunction due to structural damage to hypothalamic nuclei, which regulate appetite, temperature, diurnal rhythms and emotions. In addition, these tumors can secrete hormones that can cause acromegaly, Cushing disease, hyperprolactinemia, and the syndrome of inappropriate antidiuresis. Morphologic classification of these tumors has provided evidence for two classes of tumors, gangliocytomas that are composed of large neurons and neurocytomas that are comprised of small cells; these resemble the variants of magnocellular and parvocellular neurons in the hypothalamic nuclei. Biomarkers are used to classify these tumors and achieve accurate structure-function correlations. While surgery remains the mainstay of therapy, novel medical and radiopharmaceutical approaches are available for patients with progressive and/or unresectable tumors.

Rare Primary Central Nervous System Tumors in Adults: An Overview

Overall, tumors of primary central nervous system (CNS) are quite common in adults with an incidence rate close to 30 new cases/100,000 inhabitants per year. Significant clinical and biological advances have been accomplished in the most common adult primary CNS tumors (i.e., diffuse gliomas). However, most CNS tumor subtypes are rare with an incidence rate below the threshold defining rare disease of 6.0 new cases/100,000 inhabitants per year. Close to 150 entities of primary CNS tumors have now been identified by the novel integrated histomolecular classification published by the World Health Organization (WHO) and its updates by the c-IMPACT NOW consortium (the Consortium to Inform Molecular and Practical Approaches to CNS Tumor Taxonomy). While these entities can be better classified into smaller groups either by their histomolecular features and/or by their location, assessing their treatment by clinical trials and improving the survival of patients remain challenging. Despite these tumors are rare, research, and advances remain slower compared to diffuse gliomas for instance. In some cases (i.e., ependymoma, medulloblastoma) the understanding is high because single or few driver mutations have been defined. The European Union has launched European Reference Networks (ERNs) dedicated to support advances on the clinical side of rare diseases including rare cancers. The ERN for rare solid adult tumors is termed EURACAN. Within EURACAN, Domain 10 brings together the European patient advocacy groups (ePAGs) and physicians dedicated to improving outcomes in rare primary CNS tumors and also aims at supporting research, care and teaching in the field. In this review, we discuss the relevant biological and clinical characteristics, clinical management of patients, and research directions for the following types of rare primary CNS tumors: medulloblastoma, pineal region tumors, glioneuronal and rare glial tumors, ependymal tumors, grade III meningioma and mesenchymal tumors, primary central nervous system lymphoma, germ cell tumors, spinal cord tumors and rare pituitary tumors.

Hypothalamic Endocrine Tumors: An Update

The hypothalamus is the site of synthesis and secretion of a number of endocrine peptides that are involved in the regulation of hormonal activity of the pituitary and other endocrine targets. Tumors of the hypothalamus have been recognized to have both structural and functional effects including hormone hypersecretion. The classification of these tumors has advanced over the last few years, and biomarkers are now available to classify these tumors and provide accurate structure-function correlations. This review provides an overview of tumors in this region that is critical to metabolic homeostasis with a focus on advances in the diagnosis of gangliocytomas, neurocytomas, and pituicytomas that are unique to this region.

Extraventricular Neurocytoma in the Left Frontal Lobe: A Case Report and Literature Review

BACKGROUND

Neurocytoma is a rare brain neoplasm of neuroepithelial origin that occurs predominantly in the ventricular system adjacent to the interventricular foramen and septum pellucidum. However, extraventricular neurocytoma is an extremely rare entity, with poor clinical, radiologic, and histopathological characterization. Here we report a case of an extraventricular parafalcine neurocytoma in the left frontal lobe. We also examine previously reported cases of extraventricular neurocytoma in an attempt to provide an up-to-date summary of the condition.

METHODS

A literature search was performed using PubMed with specific key terms, inclusion criteria, and exclusion criteria. Selected case studies and case series were then compared, and statistical analyses were performed where appropriate. We report a 59-year-old woman presenting with weakness in her right leg and urinary incontinence. Physical examination revealed muscle strength of grade 3/5 in the right lower extremity. Brain magnetic resonance imaging showed a parafalcine mass in the left frontal lobe, with perilesional edema; the cerebral falx and lateral ventricle were shifted due to the compression. Gross total resection was performed.

RESULTS

Histopathological examination revealed a neurocytoma. Immunohistochemical staining showed diffuse positivity for synaptophysin. MIB-1 staining for Ki-67 antibody showed a labeling index of 20%. No adjuvant radiation or chemotherapy was administered. Brain computed tomography performed at a 3-month follow-up showed no signs of recurrence.

CONCLUSION

Extraventricular neurocytoma occurring in the brain parenchyma is a very rare central nervous system tumor. Its clinical and radiologic manifestations are nonspecific. The diagnosis depends on histopathological and immunohistochemical examination. Surgical resection should be the first-choice treatment.

Congenital Extra-Ventricular (Ganglio)Neurocytoma of the Brain Stem: A Case Report

Extraventricular neurocytoma (EVN) is an extremely rare tumor of neuroglial origin with a tendency toward ganglionic or glial differentiation. In the 2016 World Health Organization Classification, EVN was classified as a grade II tumor and described as a neoplasm with good outcome. However, the presence of cellular atypia is an important unfavorable prognostic factor. Here, we describe the first case of a patient with a congenital EVN localized in the brainstem. After a sub-total resection, his disease rapidly progressed despite several chemotherapies, including molecular targeting approaches. He died 13 months after diagnosis. In conclusion, we report an atypical case of EVN presenting an extremely aggressive behavior, despite the absence of cellular atypia. The brainstem origin and the age of the patient may have represented two important prognostic factors for our patient.

Adult Brain Tumors and Pseudotumors: Interesting (Bizarre) Cases

Some brain tumors results are interesting due to their rarity at presentation and overwhelming imaging characteristics, posing a diagnostic challenge in the eyes of any experienced neuroradiologist. This article focuses on the most important features regarding epidemiology, location, clinical presentation, histopathology, and imaging findings of cases considered "bizarre." A review of the most recent literature dealing with these unusual tumors and pseudotumors is presented, highlighting key points related to the diagnosis, treatments, outcomes, and differential diagnosis.

Pediatric Central Neurocytoma

Central neurocytomas are well-differentiated tumors of neuronal origin. These are relatively uncommon in the pediatric population. Anaplastic features reflected by brisk mitotic activity, microvascular proliferation, necrosis, and MIB-1 labeling index >2% or 3% have been proposed to indicate aggressive behavior. Because of its rarity, there is paucity of data regarding the histologic spectrum and outcome of central neurocytomas in children. With this short series, we describe our observations of the clinicopathologic characteristics and outcome of this tumor in children over a 5-year period.

Central Versus Extraventricular Neurocytoma in Children: A Clinicopathologic Comparison and Review of the Literature

BACKGROUND

Central neurocytomas (CN) are rare pediatric CNS tumors most often with a benign clinical course. Occasionally, these tumors occur outside the ventricles and are called extraventricular neurocytomas (EVN). We present a retrospective institutional analysis of children with neurocytoma with prolonged follow-up.

PROCEDURE

Twelve patients were diagnosed with neurocytoma at our institution between 1993 and 2004.

RESULTS

Six patients were male and the median age at diagnosis was 12 years (1.5 to 16 y). Seven patients had CN and 5 had EVN. Presenting symptoms included headaches (67%), vomiting (50%), nausea (33%), seizures (33%), and mental status changes (25%). Obstructive hydrocephalus was present at diagnosis in 42% of the cases. Younger age and seizures were more common in patients with EVN. Gross total resection (GTR) was achieved in 42% (5/12) of the patients. Patients with GTR received no adjuvant therapy upfront; 1 patient subsequently had recurrence with leptomeningeal disease. Patients with subtotal resection received additional treatment: 1 underwent reoperation (GTR), 2 patients received focal radiation, 2 patients received adjuvant chemotherapy, and 2 patients received craniospinal irradiation followed by chemotherapy. The 20-year overall survival for this cohort was 83% with event free survival of 56%. Overall survival for CNs was 100%, versus 40% for EVN. Event free survival for CNs was 57% and 53% for the EVNs. An MIB-1 fraction >2% was associated with worse prognosis.

CONCLUSIONS

Neurocytomas are rare brain tumors in children usually cured with GTR. Adjuvant focal radiation therapy and/or chemotherapy may improve disease control in cases with subtotal resection, but case-by-case analysis should be done. EVNs might be associated with worse outcome due to a higher proliferative index.

Atypical extraventricular neurocytoma in a 3-year-old girl: case report with radiological-pathological correlation

BACKGROUND

Extraventricular neurocytoma (EVN) is a rare neuronal tumor histologically similar to central neurocytoma but arising in the brain parenchyma outside the ventricles. The minority of EVNs show atypical features including increased proliferative index, microvascular proliferation, or necrosis, and are called atypical EVN. Most of atypical EVNs occur in adults, and the tumors in children are extremely rare. A radiological-pathological correlation and radiological clue to atypical EVNs have not been clarified.

CASE REPORT

We report a case of atypical EVN in a 3-year-old girl. Magnetic resonance imaging (MRI) revealed an extraventricular intraparenchymal tumor in the left frontal lobe, which was composed of homogeneous well-demarcated cystic component and peripheral ill-delineated solid component with enhancement. Angiography demonstrated vascular proliferation and arteriovenous shunting in the tumor. Histologically, the resected tumor was diagnosed as atypical EVN. Types of the tumor borders (well-circumscribed or infiltrative) and MRI findings correlated closely. Morphology of the tumor vasculature was remarkable for microvascular proliferation and dilated, thickened veins, which corresponded to the angiographic features.

CONCLUSION

Although rare, atypical EVN should be included in the differential diagnosis of a cystic mass in the cerebral hemispheres in children. Radiological evaluation of tumor borders and angiographic characteristics might be useful for predicting atypicality of the tumor.

Localized overexpression of alpha-internexin within nodules in multinodular and vacuolating neuronal tumors

Multinodular and vacuolating neuronal tumors (MVNT) have been recently referred to as a distinctive neuronal tumor entity based on histopathological findings. They are characterized by multiple tumor nodules, vacuolar alteration and widespread immunolabeling for human neuronal protein HuC/HuD. Only 13 cases have been reported in the literature to date and little is known about the histopathology of these tumors. Herein, we report a case of MVNT with additional confirmation of immunohistochemical features. A 22-year-old woman presented with a continuous headache. MRI showed a subcortical white matter lesion with multiple satellite nodules in the frontal lobe appearing as T2/fluid-attenuated inversion recovery (FLAIR) hyperintensities. Histological examination of the resected lesion revealed well-defined multiple nodules composed of predominant vacuolating tumor cells. The tumor cells exhibited consistent immunolabeling for doublecortin, as well as HuC/HuD, both representative neuronal biomarkers associated with earlier stages of neuronal development. Immunopositivity for oligodendrocyte transcription factor 2 (Olig2) and S100 was also detected in tumor cells. Additionally, significant overexpression of alpha-internexin was observed in the background neuropil limited to tumor nodules. Neuronal nuclear antigen (NeuN), synaptophysin and neurofilament, markers for mature neurons, were either negative or weakly positive. The expression profile of neuronal biomarkers can be distinguished from that of classic neuronal tumors and is the immunohistochemical hallmark of MVNT. In summary, we identified the characteristic tumoral expression of HuC/HuD and doublecortin and the presence of abundant neuropil localized in MVNT tumor nodules, which exhibited widespread alpha-internexin expression. These results supported the presumption that MVNT is a distinct histopathological entity.

Neurocytoma of the pituitary gland: A case report and literature review

Extraventricular neurocytomas (EVN) are rare central nervous system tumors, often located within the cerebral hemisphere. The present study reports a case of a 56-year-old male patient with bitemporal hemianopsia. Computed tomography and magnetic resonance imaging revealed a tumor in the sellar region. The tumor was totally excised. Postoperative histological examination of the tumor demonstrated that synaptophysin, chromogranin-A and neuron-specific enolase were positive, while luteinizing hormone, follicle-stimulating hormone, growth hormone, prolactin, adrenocorticotropic hormone, thyroid-stimulating hormone, glial fibrillary acidic protein, S-100, nestin and epithelial membrane antigen were negative, which were the main pathological features of neurocytomas. This is the fourth case of EVN located in the sellar region reported. The associated studies are also reviewed.

Behavioral disorders as unusual presentation of pediatric extraventricular neurocytoma: report on two cases and review of the literature

BACKGROUND

Extraventricular neurocytomas (EVNs) are rare parenchymal brain tumors, distinct from central neurocytomas that are typically located within the supratentorial ventricular system. Seizures and headache represent the most common symptoms of extraventricular neurocytomas in the cerebral hemisphere both in adult and pediatric population.

CASE PRESENTATION

We describe two cases of pediatric EVN with clinical onset characterized by behavioral and attention deficit/ hyperactivity disorders. The association between behavioral/attention disorders in childhood and the presence of a frontal neurocytoma has never been described before. Furthermore, inappropriate levels of inattention, hyperactivity and impulsivity are common among the neurobehavioral and developmental disorders in childhood. We reviewed 43 pediatric cases of extraventricular neurocytoma included in the PubMed database and their clinical presentation, and we never found this unusual relationship.

CONCLUSION

In childhood, the attention/hyperactivity disorders seem to be often over-diagnosed. When these deficits are more subtle and do not well-fit in a specific neurocognitive disorder, the clinicians should have a suspicion that they might mask the clinical features of a frontal lesion. This paper is focused on the clinical presentation of the extraventricular neurocytoma and the possible organic etiology of an attention and hyperactivity deficit.

Primary central neurocytoma of the mesencephalic tectum in a pediatric patient

PURPOSE

Neurocytomas are tumors or neuronal differentiation, typically located within the supratentorial ventricular system. The extraventricular location is uncommon. A limited number of cases involving the brainstem have been reported and may be misdiagnosed as brainstem gliomas. Furthermore, midbrain neurocytomas are extremely rare, and no similar cases in pediatric patients have been reported in the literature to date. Brainstem location of neurocytomas often precludes gross total removal of the lesion, and in these cases, adjuvant therapies may be helpful.

METHODS

We report a case of a 16-year-old child who presented with signs and symptoms of increased intracranial pressure. The magnetic resonance imaging study demonstrated the presence of a primary mesencephalic tectum lesion causing obstructive hydrocephalus. The patient underwent emergent ventriculoperitoneal shunt implantation, resolving the hydrocephalus and the clinical symptoms. The lesion was partially removed through a suboccipital craniotomy and supracerebellar infratentorial approach to the mesencephalic tectum, without intraoperative complications.

RESULTS

Histological examination of the lesion was consistent with the diagnosis of extraventricular neurocytoma. The patient was referred to the oncology department for additional treatment with Gamma Knife radiosurgery.

CONCLUSIONS

Although brainstem neurocytoma is rare, this case demonstrates that it should be included in the differential diagnosis of brainstem gliomas. Because of brainstem tumor location, complete surgical removal may be challenging or not possible, with a high risk of postoperative neurological deficits. Adjuvant therapies may prevent local tumor growth in cases of tumor remnants or recurrences following microsurgery in selected cases.

Visual and auditory hallucinations revealing cerebellar extraventricular neurocytoma: uncommon presentation for uncommon tumor in uncommon location

OBJECTIVE

Visual and auditory hallucinations in relation to a cerebellar tumor are rarely reported in children. Primary origin of extraventricular neurocytoma (EVN) in the cerebellum is very rare.

CLINICAL PRESENTATION

We report on a case of a cerebellar EVN in a 13-year-old girl with the initial symptoms of psychiatric manifestations for more than 2 months. Magnetic resonance imaging of the brain revealed a patchy enhanced tumor in the paramedian left cerebellar region. No obstructive hydrocephalus was noted.

INTERVENTION

Total surgical removal of the tumor was performed. The tumor was initially diagnosed as an oligodendroglioma. After special immunohistochemical studies, the final definitive diagnosis was an EVN without isocitrate dehydrogenase mutation.

CONCLUSION

EVNs located in the cerebellum are extremely rare. We discuss the clinical symptoms and histological-immunohistochemical features of this rare tumor in that rare location.

Extraventricular neurocytoma in pediatric populations: A case report and review of the literature

Extraventricular neurocytomas (EVNs) are rare neuronal tumors included in the definition of neoplasms in the 2007 World Health Organization classification of tumors of the central nervous system. Although a small case series of EVNs in adults has been previously reported, EVNs in pediatric populations are extremely rare. The current case report presents the clinicopathological features of an EVN in a 2-year-old female who presented with nausea and vomiting that had lasted for five days. In addition, an analysis of the imaging features, histology, treatment and prognosis of these reported rare lesions is presented. Immunohistochemically, EVNs are characterized by the robust expression of synaptophysin, but with a lack of oligodendrocyte transcription factor 2, isocitrate dehydrogenase enzyme isoform 1 (IDH1) R132/IDH2 R172 mutations and p53 immunoexpression. The treatment for EVNs in pediatric and adult populations is gross total resection, with post-operative radiation reserved for subtotal resection or recurrent disease. In addition, drop metastasis must be carefully avoided.