Long-term outcomes of primarily metastatic juvenile pilocytic astrocytoma in children

A nine-month-old boy with regression of milestones and severe constipation: an unusual case of a large spinal NTRK1 fusion pilocytic astrocytoma

INTRODUCTION

Pilocytic astrocytoma, a World Health Organization grade 1 tumor, is the most common brain tumor in children between 5 and 14 years of age and the second most common in children younger than 5 and older than 14. Although classical to the cerebellum and hypothalamic regions, it can also arise in the spinal cord. Larotrectinib, a selective inhibitor of tropomyosin receptor kinase, has been effective in pediatric tumors with NTRK fusion mutations in children as young as 1-month-old.

CASE

We share the case of a 9-month-old boy who presented with a 4-month history of regression of his milestones and severe constipation who was found to have a large spinal pilocytic astrocytoma with multiple intracranial periventricular lesions.

Immunotherapy for Pediatric Brain and Spine Tumors: Current State and Future Directions

BACKGROUND

Brain tumors are the most common solid tumors and the leading cause of cancer-related deaths in children. Incidence in the USA has been on the rise for the last 2 decades. While therapeutic advances in diagnosis and treatment have improved survival and quality of life in many children, prognosis remains poor and current treatments have significant long-term sequelae.

SUMMARY

There is a substantial need for the development of new therapeutic approaches, and since the introduction of immunotherapy by immune checkpoint inhibitors, there has been an exponential increase in clinical trials to adopt these and other immunotherapy approaches in children with brain tumors. In this review, we summarize the current immunotherapy landscape for various pediatric brain tumor types including choroid plexus tumors, embryonal tumors (medulloblastoma, AT/RT, PNETs), ependymoma, germ cell tumors, gliomas, glioneuronal and neuronal tumors, and mesenchymal tumors. We discuss the latest clinical trials and noteworthy preclinical studies to treat these pediatric brain tumors using checkpoint inhibitors, cellular therapies (CAR-T, NK, T cell), oncolytic virotherapy, radioimmunotherapy, tumor vaccines, immunomodulators, and other targeted therapies.

KEY MESSAGES

The current landscape for immunotherapy in pediatric brain tumors is still emerging, but results in certain tumors have been promising. In the age of targeted therapy, genetic tumor profiling, and many ongoing clinical trials, immunotherapy will likely become an increasingly effective tool in the neuro-oncologist armamentarium.

Recent Progress in the Pathology and Genetics of Pilocytic and Pilomyxoid Astrocytomas

Pilocytic and pilomyxoid astrocytomas are some of the most common gliomas in children and young adults. These gliomas are indolent neoplasms with long overall survival probability. The genetic characteristics of these neoplasms are well known, and our deepened understanding of their associated molecular alterations has led to the development of novel treatment strategies and approaches. Currently, we can account for some of the unusual behavior, such as oncogene-induced senescence, associated spontaneous regression, anaplastic transformation, and cerebrospinal dissemination, of these gliomas. Nevertheless, enigmatic issues continue to surround these chronic tumors. Here, we review the classical and uncommon clinical pathological and genetic features of these indolent gliomas.

Simultaneous Supratentorial and Infratentorial Pilocytic Astrocytomas in an Adult Patient with Concurrent Neurofibromatosis Type 1 and HIV Infection

BACKGROUND

Neurofibromatosis type 1 (NF1) has been identified as a predisposing factor in the development of pilocytic astrocytoma (PA), a common benign central nervous system tumor. Although this is a common association, simultaneous development of multiple lesions is an infrequent finding, especially in nonoptic and hypothalamic locations.

CASE DESCRIPTION

A 41-year-old female patient with NF1 and uncontrolled human immunodeficiency virus (HIV) type 1 infection presented with a first generalized seizure and associated headache and ataxia. Imaging studies revealed 2 large intra-axial PAs, nodular-cystic in the supratentorial compartment and solid in the infratentorial compartment. Both lesions were treated by gross total resection in 2 surgeries performed 1 week apart. Despite their different imaging patterns, the tumors were histologically and genetically identical.

CONCLUSIONS

We present a unique case involving 2 histologically and genetically identical PAs occurring simultaneously in supratentorial and infratentorial locations. We suggest that an intrinsic predisposition to tumor development in patients with NF1 might have been enhanced by the HIV-related immunosuppression in this case. Strict oncologic surveillance is essential in patients with a tumor predisposition syndrome combined with immunosuppression.

Dysembryoplastic neuroepithelial tumor-like pilocytic astrocytoma: A case report

RATIONALE

Pilocytic astrocytoma (PA) typically shows biphasic pattern with a mixture of loose microcystic and compact regions, in which it is not uncommon to see heterogeneous morphology. However, there has not been reported in the literatures of the PA type that shows similarity to dysembryoplastic neuroepithelial tumor (DNT) in both histological morphology and immunophenotype.

PATIENT CONCERNS

The present study described a case of PA affecting the right temporal-occipital lobe in a 22-year-old male patient. Morphologically, it composed of totally distinctive microcystic pattern. The classical biphasic pattern of PA was not observed. Immunohistochemically, neuronal marker NeuN was expressed in tumor cells scattered in the background which simulated its expression morphology in DNT. However, KIAA1549-BRAF fusion gene was identified by fluorescence in situ hybridization (FISH), supporting for the diagnosis of PA.

DIAGNOSES

DNT-like PA (WHO grade I).

INTERVENTIONS

The tumor was totally removed via a right temporal-occipital craniotomy.

OUTCOMES

The patient is free of local recurrence and dissemination eleven months after surgical resection of the lesion.

LESSONS

We herein report a rare case of DNT-like PA. For diagnosis, KIAA1549-BRAF fusion gene should be detected under similar situation.