Primary intracranial neuroendocrine tumor: two case reports

A primary sphenoclival skull base neuroendocrin tumor: A rare case report and literature review

INTRODUCTION AND IMPORTANCE

Primary intracranial neuroendocrine tumors (NETs) are exceedingly rare, often posing diagnostic challenges, particularly in non-secreting variants. These tumors may initially present with nonspecific symptoms, leading to delayed diagnosis and potential neurological complications.

CASE REPORT

We present the case of a 33-year-old male admitted with a one-year history of progressively worsening headache accompanied by acute left ptosis and diplopia. Initial examination revealed left eye ptosis and hypotropia, indicative of third and fourth cranial nerve paralysis. Cavoscopy revealed a mild anterior wall bulge of the sphenoid with normal mucosa. MRI imaging unveiled an expansive clival process extending towards the sellar region and left cavernous sinus, completely occupying the sphenoid sinus and exerting mass effect on the pituitary stalk. Hormonal assays were within reference ranges, ruling out a hormonally-active tumor. Endoscopic endonasal surgery for biopsy revealed a low-grade neuroendocrine tumor positive for cytokeratin AE1/AE2, chromogranin A, synaptophysin, and beta-catenin, with a Ki-67-labeling index <2 %. Somatostatin receptor scintigraphy confirmed intense hyper fixation of the tracer in the sphenoidal tumor, supporting its neuroendocrine origin. The patient declined surgical intervention after informed consent, opting for C1 somatostatin analogs prior to radiotherapy. One-year follow-up demonstrated symptom stability with no tumor progression.

CLINICAL DISCUSSION

To this day, no consensus among reports concerning the optimal management of these cases. Imaging assessment is crucial to validate the primary nature of the tumor and to exclude any distant localization. Various therapeutic modalities, such as surgery, radiotherapy, and somatostatin analogs, should be considered based on the specific characteristics and extent of the tumor.

CONCLUSION

Our case is a clear reminder that neuroendocrine tumors should be considered as a differential diagnosis for skull base neoplasms.

Paraneoplastic neurologic manifestations of neuroendocrine tumors

Neuroendocrine neoplasms (NENs) are a heterogeneous group of tumors arising from the transformation of neuroendocrine cells in several organs, most notably the gastro-entero-pancreatic system and respiratory tract. The classification was recently revised in the 5th Edition of the WHO Classification of Endocrine and Neuroendocrine Tumors. NENs can rarely spread to the central or peripheral nervous systems. Neurologic involvement is determined by the rare development of paraneoplastic syndromes, which are remote effects of cancer. Mechanisms depend on immunologic response to a tumor, leading to the immune attack on the nervous system or the production of biologically active ("functioning") substances, which can determine humoral (endocrine) effects with neurologic manifestations. Paraneoplastic neurologic syndromes (PNS) are immunologically mediated and frequently detected in small cell lung cancer but rarely seen in other forms of NEN. PNS and Merkel cell carcinoma is increasingly reported, especially with Lambert Eaton myasthenic syndrome. Endocrine manifestations are found in a wide spectrum of NENs. They can develop at any stage of the diseases and determine neurologic manifestations. Patient outcomes are influenced by tumor prognosis, neurologic complications, and the severity of endocrine effects.

Primary Pituitary Carcinoids Do Not Exist: A Reappraisal in the Era of Pituitary Neuroendocrine Tumours

The World Health Organization classification of pituitary tumours, published in 2022, supported a change in the terminology from "pituitary adenoma" to "pituitary neuroendocrine tumour" (PitNET). The neuroendocrine cells represent an integral part of the diffuse neuroendocrine system, including, among others, thyroid C cells, the parathyroid chief cells, and the anterior pituitary. Normal and neoplastic adenohypophyseal neuroendocrine cells have light microscopic, ultrastructural features and an immunoprofile compatible with the neuroendocrine cells and neuroendocrine tumours from other organs. Moreover, neuroendocrine cells of pituitary origin express transcription factors which indicate their cell-lineage origin. Thus, pituitary tumours are now considered as a continuum with other neuroendocrine tumours. PitNETs may occasionally be aggressive. In this context, the term "pituitary carcinoid" has no specific meaning: it either represents a PitNET, or a metastasis to the pituitary gland of a neuroendocrine tumour (NET). An accurate pathological evaluation, combined where necessary with functional radionuclide imaging, can define the origin of the tumour. We recommend that clinicians liaise with patient groups to understand the terminology to define primary tumours of adenohypophyseal cells. It is incumbent upon the responsible clinician to explain the use of the word "tumour" in a given clinical context.

The "chameleon" sellar lesions: a case report of unexpected sellar lesions

Introduction

The sellar region and its boundaries represent a challenging area, harboring a variety of tissues of different linings. Therefore, a variety of diseases can arise or involve in this area (i.e., neoplastic or not). A total of three challenging cases of "chameleon" sellar lesions treated via EEA were described, and the lesions mimicked radiological features of common sellar masses such as craniopharyngiomas and/or pituitary adenomas, and we also report a literature review of similar cases.

Methods

A retrospective analysis of three primary cases was conducted at the Università degli Studi di Napoli Federico II, Naples, Italy. Clinical information, radiological examinations, and pathology reports were illustrated.

Results

A total of three cases of so-called "chameleon" sellar lesions comprising two men and one woman were reported. Based on the intraoperative finding and pathological examination, we noticed that case 1 had suprasellar glioblastoma, case 2 had a primary neuroendocrine tumor, and case 3 had cavernous malformation.

Conclusion

Neurosurgeons should consider "unexpected" lesions of the sellar/suprasellar region in the preoperative differential diagnosis. A multidisciplinary approach with the collaboration of neurosurgeons, neuroradiologists, and pathologists plays a fundamental role. The recognition of unusual sellar lesions can help surgeons with better preoperative planning; so an endoscopic endonasal approach may represent a valid surgical technique to obtain decompression of the optic apparatus and vascular structures and finally a pathological diagnosis.

Primary Neuroendocrine Carcinoma of Pineal Gland With Extensive Meningeal Metastasis Detected by 18F-NOTATATE PET/CT

ABSTRACT

Primary neuroendocrine tumor of the pineal gland is a rare disease. A 44-year-old woman with right cerebellopontine angle metastatic small cell neuroendocrine carcinoma underwent 18F-FDG and 18F-NOTATATE PET/CT scans. 18F-NOTATATE PET/CT showed intense uptake in the pineal gland lesions and multiple foci of intense focus of uptake in the intracranial leptomeningeal and whole spinal canal. However, the lesions are less impressive on 18F-FDG PET/CT.

Primary Neuroendocrine Carcinoma of the Cerebellopontine Angle: A Case Report and Literature Review

Primary intracranial neuroendocrine tumors are extremely rare malignancies with very few cases reported in the world literature. We describe a primary neuroendocrine carcinoma arising from the right cerebellopontine angle, the second case that has been described in this location. The possible origin in this place and treatment are described.

A 29-year-old male patient, diagnosed with schwannoma of the right cerebellopontine angle, and treated with radiosurgery at another institution, came to our hospital six months later, The patient presented with a history of rapid progression of numbness on the right side of the face, diplopia, dizziness, vomiting, and facial palsy. On examination, the right cranial nerves V, VI, VII, VIII, and IX were affected. The MRI showed tumor growth occupying the right cerebellopontine angle, with compression of the brain stem and cerebellum. A right retromastoid craniectomy removed the tumor partially and the histopathological examination revealed a high-grade neuroendocrine carcinoma.

We describe a primary neuroendocrine tumor of the brain that, despite its rarity, must be considered in the differential diagnosis. There are currently no guidelines for the management of these tumors. According to previously reported cases, surgery is the first line of treatment, followed by radiotherapy or chemotherapy. We consider that such a rare case is needed to be reported for a better understanding of the disease and its neurobiology.

Unique Finding of a Primary Central Nervous System Neuroendocrine Carcinoma in a 5-Year-Old Child: A Case Report

Neuroendocrine tumors (NETs) are rare neoplasms predominantly arising in the gastrointestinal-tract or the lungs of adults. To date, only ten cases of primary central nervous system (CNS) NETs have been reported, with just three of them describing a neuroendocrine carcinoma (NECA) and none occurring in a child. We report on a previously healthy 5-year-old boy, who presented with headaches, nausea and vomiting, and was diagnosed with a left cerebellar solid mass with a cystic component. After gross-total resection, histology revealed a neuroendocrine carcinoma. Molecular analysis of the tumor tissue showed a KRAS-splice-site mutation (c451-3C &gt; T). The KRAS-mutation was discovered to be a maternal germline mutation, previously described as likely benign. After extensive search for an extracranial primary tumor, including Ga-68 DOTANOC-PET-CT, the diagnosis of a primary CNS NECA was established, and proton irradiation was performed. Unfortunately, the patient developed an in-field recurrence just 5 weeks after the end of radiotherapy. The tumor was re-resected with vital tumor tissue. Six cycles of chemotherapy were initiated, consisting of cisplatin, carboplatin, etoposide and ifosfamide. The patient remains disease free 22 months after the end of treatment, supporting the beneficial effect of platinum- and etoposide-based chemotherapy for this tumor entity.

Primary neuroendocrine tumor of the pineal gland: a case report

INTRODUCTION

Primary intracranial neuroendocrine tumors are exceedingly rare, with few cases in the literature. We present a case of a primary neuroendocrine carcinoma of the pineal gland, which is the second that has ever been reported.

CASE PRESENTATION

A 53-year-old male patient presented with vomiting, weakness, and headaches. Imaging revealed a lesion in the pineal region, which was surgically resected. This mass was characterized by histology as a neuroendocrine carcinoma, given the presence of neuroendocrine markers and cytokeratin markers with absence of a primary lesion elsewhere on imaging.

CONCLUSIONS

There are currently no guidelines on the management of primary intracranial neuroendocrine tumors. In this case, the patient underwent surgical resection and craniospinal radiotherapy. He subsequently received one cycle of chemotherapy with temozolomide, an alkylating agent, but he unfortunately did not tolerate treatment. A multidisciplinary decision was made along with the patient and his family to focus on palliative care. Eighteen months after the initial presentation, disease recurred in the patient's neck. The patient underwent resection to control the metastases, with a plan to follow with radiotherapy and chemotherapy. Unfortunately, the patient became unwell and died at 21 months after initial diagnosis. This demonstrates a need for continued research and reporting on this uncommon disease entity.

Unusual cause of a painless soft tissue mass of the scalp: a rare presentation of primary intracranial neuroendocrine neoplasm

Incidental soft tissue lumps in the scalp are a common presenting complaint in clinical practice. However, they may signify more sinister underlying pathologies. Our report examines a 63-year-old man presenting with impaired co-ordination in his left hand following a 3-month history of a painless left retroauricular scalp lump. MRI revealed a large left occipital soft tissue mass eroding through the underlying skull with infiltration into the underlying cerebellum and temporal lobe. Open biopsy confirmed a diagnosis of high-grade intracranial neuroendocrine tumour (NET). At approximately 5 months following successful tumour resection and adjuvant chemotherapy, he developed tumour recurrence and was subsequently palliated, and died at 1 year post diagnosis. Herein, we review other cases of primary intracranial NET, clinical findings, histopathological features and prognosis.

Pituitary Neoplasm Nomenclature Workshop: Does Adenoma Stand the Test of Time?

The WHO Classification of Endocrine Tumours designates pituitary neoplasms as adenomas. A proposed nomenclature change to pituitary neuroendocrine tumors (PitNETs) has been met with concern by some stakeholder groups. The Pituitary Society coordinated the Pituitary Neoplasm Nomenclature (PANOMEN) workshop to address the topic. Experts in pituitary developmental biology, pathology, neurosurgery, endocrinology, and oncology, including representatives nominated by the Endocrine Society, European Society of Endocrinology, European Neuroendocrine Association, Growth Hormone Research Society, and International Society of Pituitary Surgeons. Clinical epidemiology, disease phenotype, management, and prognosis of pituitary adenomas differ from that of most NETs. The vast majority of pituitary adenomas are benign and do not adversely impact life expectancy. A nomenclature change to PitNET does not address the main challenge of prognostic prediction, assigns an uncertain malignancy designation to benign pituitary adenomas, and may adversely affect patients. Due to pandemic restrictions, the workshop was conducted virtually, with audiovisual lectures and written précis on each topic provided to all participants. Feedback was collated and summarized by Content Chairs and discussed during a virtual writing meeting moderated by Session Chairs, which yielded an evidence-based draft document sent to all participants for review and approval. There is not yet a case for adopting the PitNET nomenclature. The PANOMEN Workshop recommends that the term adenoma be retained and that the topic be revisited as new evidence on pituitary neoplasm biology emerges.

Contribution of Immune-Mediated Paraneoplastic Syndromes to Neurological Manifestations of Neuroendocrine Tumours: A Retrospective Study

INTRODUCTION

Neurological symptoms associated with neuroendocrine tumours (NETs) may be related to metastatic disease or paraneoplastic syndromes (PNSs); these last are often associated with autoantibodies targeting various onconeural antigens. To better characterize neurological PNSs related to NETs, we report the largest case-series study to date.

METHODS

We retrospectively reviewed the charts of all patients diagnosed with NETs of the gastrointestinal tract who presented with neurological symptoms at either of 2 tertiary academic hospitals (Henri Mondor and Beaujon, France) between 1994 and 2016. All patients underwent extensive neurological tests including clinical, laboratory, and radiological investigations. The clinical response to immunomodulating agents was recorded.

RESULTS

In the 13 identified patients, the most common presentations were peripheral neuropathy (46.2%) and encephalopathy (26.6%). Of the 6 (53.3%) patients whose serum anti-neuronal antibodies were assayed, 5 had high titres. Short-term oral corticosteroid and immunosuppressant drug therapy was given to 4 of these patients, of whom 3 had a clinical response and 1 no response. Repeated high-dose intravenous immunoglobulin therapy induced a complete clinical response in 1 patient. Encephalopathy resolved fully after hepatectomy or intrahepatic chemoembolization for liver metastases in another 2 patients.

DISCUSSION

The neurological symptoms associated with NETs may be due in part to autoimmune PNS. Based on experience at our 2 centres, we estimate that autoimmune PNS occurs in about 1% of patients with NETs. Early symptom recognition allows the initiation of effective treatments including corticosteroids, immunosuppressive drugs, and/or intravenous immunoglobulins.

Primary Intracranial Neuroendocrine Tumor of the Skull Base Complicated with Tension Pneumocephalus after Radiotherapy

Neuroendocrine tumors (NETs) are neoplasms that originate from cells of the endocrine and nervous systems, and are commonly found in the gastrointestinal and respiratory tracts. Primary intracranial NETs are extremely rare and have been the focus of only a few studies thus far. Herein, we report the case of a primary intracranial NET of the skull base complicated with tension pneumocephalus after radiotherapy. An 84-year-old woman visited a local hospital for a head injury, and CT revealed a skull base tumor. MRI showed that the tumor was located mainly on the clivus and extended into the paranasal sinuses and nasal cavity. We biopsied the tumor via the nasal cavity, and the pathological diagnosis was NET, WHO grade 2. We subsequently administered focal intensity-modulated radiation therapy, but the patient developed tension pneumocephalus 1 year after radiotherapy. We therefore performed endoscopic transnasal cerebrospinal fluid leak closure with a nasoseptal flap. The postoperative course was successful, and the patient returned home but died of an unknown cause 2 years after discharge. The optimal postoperative management of primary intracranial NETs remains controversial. Tension pneumocephalus related to radiotherapy is a rare complication. Assessing skull bone erosion before radiotherapy and performing regular radiological follow-up examinations are essential to prevent this rare complication.

Primary skull base neuroendocrine carcinoma—a case report and review of literature

Skull-based neuroendocrine carcinomas are rare tumors with only a few case reports in literature. Here we present an unusual case of primary neuroendocrine carcinoma of the skull in 60-year-old male which was proven on surgical biopsy. The imaging features of this rare tumor along with differential diagnosis are discussed with brief review of the literature.

Canine adrenocorticotropic hormone-producing sinusoidal neuroendocrine tumor associated with Cushing's disease

An 18-year-old male Yorkshire Terrier was admitted with a history of neurological signs including dullness and progressive tetraparesis. Physical examination revealed bilaterally symmetrical alopecia and pot-bellied abdomen. Computed tomography and necropsy examination showed a mass across the frontal sinus and cerebral frontal lobe, bilateral adrenocortical hyperplasia, and hepatomegaly. Histopathologically, the tumor lesions consisted of sheets, nests, or cords of small- to medium-sized round-to-polyhedral cells. Adrenal cortex showed bilateral diffuse cellular proliferation, and some hepatocytes showed intracytoplasmic glycogen accumulation. Immunohistochemically, the tumor cells were positive for pancytokeratin, chromogranin-A, neuron-specific enolase, S100, synaptophysin, and thyroid transcription factor-1 but negative for microtubule-associated proein-2 and neurofilament, leading to the diagnosis of neuroendocrine tumor. These tumor cells were also positive for adrenocorticotropic hormone.

Primary neuroendocrine carcinoma of the brain

Neuroendocrine neoplasms (NENs) are malignancies with rare reports of central nervous system development. A 34-year-old woman was found to have a primary NEN of the brain, and she had recurrence with identical histology 10 years later. Extracranial NENs were excluded. She had routine surveillance for the first 5 years with MRIs and positron emission tomography/CTs after the initial presentation which was treated with radiation followed by cisplatin and etoposide. This case highlights the difference in primary NENs versus NEN metastases to the brain, and that longer periods of surveillance are likely required for primary NENs. This is important because the prognosis between primary NENs and metastatic NENs to the brain are vastly different and should not be treated as equal diseases. The patient eventually died of her recurrence secondary to complications of a ventriculoperitoneal shunt placed for treatment of hydrocephalus from the disease.

Primary pituitary neuroendocrine tumor: Case report and literature review

BACKGROUND

Neuroendocrine tumors (NET) originate from the diffuse neuroendocrine system. These can arise in almost every organ of the body, although they are most commonly found in the gastrointestinal tract and respiratory system. The skull base and sellar region are extremely rare sites for neuroendocrine carcinoma. Consequently, in this case, both diagnosis and definition of surgical goals, as well as further treatment strategies were challenging.

CASE DESCRIPTION

A 65-year-old woman was admitted to our Neurosurgery Department with a rapidly progressive visus reduction, drowsiness, polyuria, and polydipsia. Neuroimaging showed a sellar/suprasellar mass (diameter of 2 cm) with a heterogeneous signal compressing the optic chiasm and extending laterally toward the cavernous sinus. Differential diagnosis based on imaging included pituitary macroadenoma or metastasis. The patient underwent endoscopic endonasal transsphenoidal surgery. A total resection of the mass was impossible because of the infiltration of the optic chiasm and the intraoperative histological diagnosis of malignant epithelial neoplasm. Further histological evaluation revealed that the lesion was a NET with no other primary or metastatic sites detectable. Subsequently, the patient was successfully treated with fractioned stereotactic radiotherapy and polychemotherapy. Four years after the surgery, follow-up magnetic resonance imaging showed stability of the residual disease. Neurologic examination revealed a complete visual recovery.

CONCLUSIONS

Primary pituitary NET, though rare, should be included in the differential diagnosis of sellar lesions. A multimodality treatment approach is needed. Finally, the present case highlights, that in the case of a pituitary lesion infiltrating the optic chiasm, including NET, the endoscopic endonasal transsphenoidal subtotal resection followed by fractioned stereotactic radiotherapy and chemotherapy may represent an effective and safe choice of treatment.