Optic nerve pilomyxoid astrocytoma: Intraoperative squash smear cytology of a rare entity

Pilomyxoid astrocytoma [PMA] is a rare, recently described variant of pilocytic astrocytoma with unique clinical and histopathological characteristics. It typically affects the optico-chiasmatic and hypothalamic region in infants and young children. Though the pilocytic astrocytoma is the commonest tumor of the optic nerve, pilomyxoid astrocytoma arising from the intraorbital part of the optic nerve is extremely rare. To the best of our knowledge, only one case of introrbital optic nerve pilomyxoid astrocytoma has been described in the English literature. We report two cases of pilomyxoid astrocytoma arising from the intraorbital optic nerve, diagnosed on intraoperative squash smear cytology and later confirmed on histopathology. Like in other locations, optic nerve pilomyxoid astrocytoma behaves in an aggressive manner.

Small Bowel Obstruction and Enterococcus Meningitis: Rare Complications of Ventriculoperitoneal Shunt Placement

A ventriculoperitoneal (VP) shunt is a commonly used mechanical device indicated for congenital and acquired hydrocephalus in children. Although VP shunt failure is not uncommon, the symptomatology and cause of failure can vary. In this case, we describe intestinal obstruction in a three-year-old Caucasian female with a history of Pilomyxoid Astrocytoma and VP shunt placement for the management of hydrocephalus. Surgical exploration revealed ischemia of the terminal ileum secondary to VP shunt tubing-induced adhesions requiring bowel resection. A secondary VP shunt infection due to Enterococcus faecalis was also noted. Our case highlights a unique presentation of intestinal obstruction and infection that should serve to increase provider suspicion when evaluating patients presenting with abdominal distention and pain with presence of a VP shunt.

A molecular study of pediatric pilomyxoid and pilocytic astrocytomas: Genome-wide copy number screening, retrospective analysis of clinicopathological features and long-term clinical outcome

Background

Pilocytic Astrocytoma (PA) is the most common pediatric brain tumors. PAs are slow-growing tumors with high survival rates. However, a distinct subgroup of tumors defined as pilomyxoid astrocytoma (PMA) presents unique histological characteristics and have more aggressive clinical course. The studies on genetics of PMA are scarce.

Methods

In this study, we report one of the largest cohort of pediatric patients with pilomyxoid (PMA) and pilocytic astrocytomas (PA) in Saudi population providing a comprehensive clinical picture, retrospective analysis with long-term follow-up, genome-wide copy number changes, and clinical outcome of these pediatric tumors. We examined and compared genome-wide copy number aberrations (CNAs) and the clinical outcome of the patients with PA and PMA.

Results

The median progression free survival for the whole cohort was 156 months and it was 111 months for the PMA, however, not statistically significantly different between the groups (log-rank test, P = 0.726). We have identified 41 CNAs (34 gains and 7 losses) in all tested patients. Our study yielded the previously reported KIAA1549-BRAF Fusion gene in over 88% of the tested patients (89% and 80% in PMA and PA, respectively). Besides the fusion gene, twelve patients had additional genomic CNAs. Furthermore, pathway and gene network analyses of genes in the fusion region revealed alterations in retinoic acid mediated apoptosis and MAPK signaling pathways and key hub genes that may potentially be involved in tumor growth and progression, including BRAF, LUC7L2, MKRN1, RICTOR, TP53, HIPK2, HNF4A, POU5F, and SOX4.

Conclusion

Our study is the first report of a large cohort of patients with PMA and PA in the Saudi population that provides detailed clinical features, genomic copy number changes, and outcome of these pediatric tumors and may help better diagnosis and characterization of PMA.

Pilomyxoid astrocytoma of the thoracic spinal cord: Extremely rare case report of over 70-year-old patient

The Pilomyxoid is rare tumor in elderly population, in addition to the occurrence of an isolated lesion in spinal cord is extremely rare in non-pediatric population. Taking biopsy and subtotal resection is the starting point in essential approach for the treatment. After defining the histopathological nature of the tumor and specified that is Pilomyxoid, the next step is the combination of reoperation and adjuvant therapy.

Dual activating FGFR1 mutations in pediatric pilomyxoid astrocytoma

BACKGROUND

Pilomyxoid astrocytomas are an aggressive subtype of astrocytoma, not graded by WHO, frequently located in hypothalamic/chiasmatic region, affecting diencephalic structures, and characterized by shorter survival and high recurrence rates. Pilomyxoid astrocytoma management remains controversial, with pathologic tissue diagnosis and relief of mass effect being the main goals of surgery while avoiding treatment-related morbidity, including vision loss, panhypopituitarism, and hypothalamic dysfunction. Chemotherapy (typically vincristine and carboplatin) in all pediatric patients and radiation therapy in pediatric patients over 5 years of age are used for treatment.

METHODS

We report clinical presentation, surgical management, and whole exome sequencing results in a pediatric patient with the subtotally resected pilomyxoid astrocytoma.

RESULTS

We identified two somatic activating missense mutations affecting FGFR1, including FGFR1 p.K656E and FGFR1 p.V561M. While the former is a known hotspot mutation that is both activating and transforming, the latter has been described as a gatekeeper mutation imparting resistance to FGFR inhibitors. Interestingly, both mutations were present with similar variant allele frequency within the tumor.

CONCLUSION

Similar variant allele frequencies of FGFR1 p.K656E and FGFR1 p.V561M mutations in our patient's tumor suggest that these mutations may have occurred at similar time points. Use of FGFR inhibitors in addition to STAT3 or PI3K/mTOR inhibition may prove a useful strategy in targeting our patient's pilomyxoid astrocytoma.

Pilocytic Astrocytoma with Gangliocytic Differentiation to Pilomyxoid Astrocytoma-expanding the Morphological Spectrum: Case Report and Literature Review

We present a rare case of pilocytic astrocytoma (PA) with gangliocytic differentiation arising in the suprasellar/chiasmatic region in a young boy that showed a rapid regrowth after the 1^st subtotal resection and “differentiated” into pilomyxoid astrocytoma (PMA) in subsequent recurrences. The clinical course, imaging, and histological features have been described with a review of the literature. While PA is well-circumscribed, biphasic tumors with bipolar piloid cells, those arising in the diencephalic region often contain myxoid stroma, angiocentric pattern, and “intermediate” features between PA and PMA. Examples of PMA “maturing” to PA are also on record; however, PA with gangliocytic component differentiating to PMA has not been described in the literature to the best of our knowledge.

Severe Radiation Necrosis Successfully Treated With Bevacizumab in an Infant with Low-Grade Glioma and Tumor-Associated Intractable Trigeminal Neuralgia

We present a unique case of radiation necrosis in a child with brain stem low-grade glioma (LGG) presenting with trigeminal neuralgia. Despite extensive therapies, severe pain persisted. She received proton beam radiation with significant improvement. However, she developed radiation necrosis and hydrocephalus. Despite surgical correction of hydrocephalus, the patient remained critically ill. She was treated with dexamethasone and bevacizumab with rapid clinical improvement. Subsequent MRIs revealed almost complete resolution of the necrosis. This case illustrates the successful treatment of trigeminal neuralgia with radiation and a rare case of radiation necrosis in an LGG successfully treated with bevacizumab and dexamethasone.

Parietal pilomyxoid astrocytoma with recurrence in 10 months: A case report and review of literature

Pilomyxoid astrocytoma (PMA) is a new entity described in WHO 2007 classification of brain tumors. Pilocytic astrocytoma (PA) and PMA share many histopathological features with a few differences in histopathology and behavior of the tumor. This tumor is commonly located in the hypothalamic chiasmatic region. PMA behaves more aggressively than PA, with shorter progression-free survival as well as a higher rate of recurrence and CNS dissemination. We describe a case of PMA in a 10-year-old male involving left parietal lobe presenting with raised ICP features along with the follow-up. Patient was symptom free after 7 months of postoperative and 5½ months of post-radiation. The unusual site and atypical Magnetic resonance imaging features are distinctive in this case report.

Pilomyxoid Astrocytoma Occurring in the Third Ventricle

Pilomyxoid astrocytoma (PMA) is a rare central nervous system tumor that has been included in the 2007 World Health Organization Classification of Tumors of the Central Nervous System. Due to its more aggressive behavior, PMA is classified as Grade II neoplasm by the World Health Organization. PMA predominantly affects the hypothalamic/chiasmatic region and occurs in children (mean age of occurrence = 10 months). We report a case of a 24-year-old man who presented with headache, nausea, and vomiting. Brain CT and MRI revealed a mass occupying only the third ventricle. We performed partial resection. Histological findings, including monophasic growth with a myxoid background, and absence of Rosenthal fibers or eosinophilic granular bodies, as well as the strong positivity for glial fibrillary acidic protein were consistent with PMA.

Cystic pilomyxoid astrocytoma on suprasellar region in 7-year-old girl: Treatment and strategy

Pilomyxoid astrocytoma (PMA) is a recently described entity with similar features to pilocytic astrocytoma but with a rare occurrence. As a new diagnosis, no treatment guideline of PMA has been established; but generally, as for any low-grade gliomas, radical resection is performed if the location is favorable. In this report, we wished to share our experience treating the PMA. The authors presented a case of a 7-year-old girl with bitemporal hemianopia. From the history, the patient had a 4-month history of headache, following with nausea and projectile vomiting 1 week before hospital admission. Past history of seizure, weakness of left extremities, and decreased consciousness were reported. Computed tomography (CT) scanning showed acute obstructive hydrocephalus and an isohypodense mass at suprasellar region with the cystic component. We performed ventriculo-peritoneal-shunt to reduce the acute hydrocephalus, followed by craniotomy tumor removal 2 weeks later. The patient underwent radiotherapy and medical rehabilitation. Diagnosis of PMA was made on the basis of pathologic anatomy result, which showed a myxoid background with pseudorosette. Postoperative CT showed a residual tumor at right parasellar area without hydrocephalus. After the surgery, the treatment was followed with radiotherapy for 20 times within 2 months. Postradiation CT performed 1-year later showed a significant reduction of the tumor mass. There were no new postoperative deficits. The patient had improvement of the visual field and motor strength. The authors reported a case of a 7-year-old girl with PMA. Surgical resection combined with radiotherapy was performed to control the growth of PMA. More observation and further studies are required to refine the treatment methods.

Pilomyxoid Astrocytoma (PMA) Shows Significant Differences in Gene Expression vs. Pilocytic Astrocytoma (PA) and Variable Tendency Toward Maturation to PA

Pilomyxoid astrocytomas (PMAs) manifest a more aggressive clinical course than pilocytic astrocytomas (PAs). Development of effective therapies demands a better biological understanding of PMA. We first conducted gene expression microarray analysis of 9 PMA and 13 PA from infra- and supratentorial sites. Unsupervised hierarchical clustering analysis demonstrated that tumors are grouped according to anatomic site, not diagnosis. Gene expression profiles were then contrasted between eight PMAs and six PAs, all supratentorial/hypothalamic/chiasmal. Clinical outcome of PMAs varied, with four out of four patients with diencephalic syndrome succumbing to disease, one of whom showed bulky metastatic leptomeningeal spread at autopsy, with bimodal maturation to PA in some areas and de-differentiation to glioblastoma in others. A surviving child has undergone multiple surgical debulking, with progressive maturation to PA over time. Ontology-enrichment analysis identified overexpression in PMAs of extracellular matrix and mitosis-related genes. Genes overexpressed in PMA vs. PA, ranked according to fold-change, included developmental genes H19, DACT2, extracellular matrix collagens (COL2A1; COL1A1) and IGF2BP3 (IMP3), the latter previously identified as an adverse prognostic factor in PMA and PA.

Pilomyxoid astrocytoma of the cerebellar vermis in an elderly patient

Background:

Pilomyxoid astrocytoma (PMA) has recently been accepted as an aggressive variant of pilocytic astrocytoma with distinct histopathological features. PMAs have been frequently described in the pediatric population with a predilection for the hypothalamic/chiasmatic region.

Case Description:

A 72-year-old African American male presented with 6 months of memory loss, difficulty expressing himself, and a progressively worsening gait. Magnetic resonance imaging of the brain demonstrated a heterogeneously enhancing cystic mass centered within the cerebellar vermis with mass effect on the fourth ventricle and ventriculomegaly. The patient underwent placement of a ventriculoperitoneal shunt followed by a surgical resection of the lesion, which after immunohistopathologic evaluation, was diagnosed as a World Health Organization grade II PMA. The patient refused further treatment of the lesion and expired 11 months after initial symptom presentation and 4 months after surgery.

Conclusion:

To our knowledge, this is the first report of PMA of the cerebellar vermis in a previously unreported age group. This case report describes the natural history of this type of tumor in a patient who refused adjuvant therapy following surgical resection.

Pilomyxoid astrocytoma of the pineal region: cytopathological features and differential diagnostic considerations by intraoperative smear preparation

Pilomyxoid astrocytoma (PMA) is a recently identified type of pilocytic astrocytoma (PA) with shorter progression-free and overall survival, higher rate of recurrence, and higher risk of leptomeningeal spread compared to pilocytic tumors (WHO grade 2 designation). A case is presented here in which intraoperative imprint smears of a pineal region tumor in a 14-year-old girl revealed cytologic monomorphism, elongated cells with bland nuclei embedded in a myxoid background. The tumor cells possessed uniformly round nuclei with a smooth nuclear outline, fine granular chromatin, and small nucleoli. Slender cytoplasmic fibrillary processes and angiocentric arrangement were observed but Rosenthal fibers or eosinophilic granular bodies were absent. A cytologic diagnosis of PMA of the pineal region was suggested by intraoperative smear preparation. Histology and immunohistochemical results confirmed the final diagnosis. This report shows that smear preparation can be trustworthy for the intraoperative diagnosis of PMA, helping to determine the appropriate neurosurgical procedure and therapeutic implications.

Pilomyxoid astrocytoma with high proliferation index

Pilomyxoid astrocytomas is an uncommon aggressive piloid neoplasm, closely related to pilocytic astrocytomas and typically presents in the very young but can occur in older children and rarely in adults. A 12-years-old male presented with focal seizures, headache and vomiting of 10 days duration. Computed tomogram showed a hypo- to hyperdense and peripherally enhancing, solid-cystic lesion in the left temporal lobe. Histopathological examination revealed a characteristic tumor composed of bipolar cells arranged in dyscohesive sheets, angiocentric pattern in a loose myxoid background, with brisk mitotic activity and foci of necrosis. No Rosenthal fibers or eosinophilic granular bodies were seen. The tumor cells showed strong GFAP and scattered p53 positivity, but were negative for EMA. Ki-67 positivity ranged from 30 to 40%, highest reported till date. The patient was treated with radiotherapy and concurrent temozolamide and the tumor recurred after two years.

Pilomyxoid astrocytoma of the brainstem

A pilomyxoid astrocytoma is a recently described tumor that occurs predominantly in the hypothalamic-chiasmatic region and is rarely found elsewhere. It has similar features as pilocytic astrocytomas, but has distinct histological characteristics and a poorer prognosis. A pilomyxoid astrocytoma is an aggressive tumor, and increased awareness is necessary with a suspect case. We present the first case of a pilomyxoid astrocytoma of the brainstem described after the newest World Health Organization classification of central nervous system tumors.

Intramedullary pilomyxoid astrocytoma with intracerebral metastasis exhibiting oligoden-droglioma-like features

Intramedullary glioma are rare and their biological behaviour can differ from their cerebral counterparts. Pilomyxoid astrocytoma (PMA, WHO grade II), predominantly occur in the hypothalamic/chiasmatic region of infants and children. The few reported cases of pediatric intramedullary PMA displayed a particularly aggressive behavior. Here, we report a diagnostically challenging case of a five year old female patient presenting with intramedullary glioma and local tumor recurrence three years later. Twelve years after the initial manifestation, a second tumor was found intracerebrally. We performed a comprehensive histological, molecular pathological and imaging analysis of the tumors from both localizations. The results revealed a metastasizing PMA with unique histological and genetic features. Our study indicates that PMA comprise a heterogeneous group including aggressive subtypes which may not be compatible with the current classification according to WHO grade II. Furthermore, the case emphasizes the increasing relevance of molecular pathological markers complementing classic histo-logical diagnosis.