Durable benefit and change in TCR clonality with nivolumab in a Lynch syndrome-associated glioma.

Germline replication-repair deficient (gRRD) gliomas are exceptional events, and only a few of them have been treated with immune checkpoint inhibitors (ICIs). Contrary to sporadic gliomas, where ICIs have failed to show any objective benefit, the very few patients with gRRD gliomas treated with ICIs to date seem to benefit from programmed-death-1 (PD-1) inhibitors, such as nivolumab or pembrolizumab, either in terms of durable responses or in terms of survival. T-cell immunohistochemistry (IHC) and T-cell receptor (TCR) repertoire using high-throughput next-generation sequencing (NGS) with the Oncomine TCR-Beta-SR assay (Thermo Fisher Scientific) were analyzed in pre- and post-nivolumab tumor biopsies obtained from a patient with a Lynch syndrome-associated glioma due to a germline pathogenic hMLH1 mutation. The aim was to describe changes in the T-cell quantity and clonality after treatment with nivolumab to better understand the role of acquired immunity in gRRD gliomas. The patient showed a slow disease progression and overall survival of 10 months since the start of anti-PD-1 therapy with excellent tolerance. A very scant T-cell infiltrate was observed both at initial diagnosis and after four cycles of nivolumab. The drastic change observed in TCR clonality in the post-nivolumab biopsy may be explained by the highly spatial and temporal heterogeneity of glioblastomas. Despite the durable benefit from nivolumab, the scant T-cell infiltrate possibly explains the lack of objective response to anti-PD-1 therapy. The major change in TCR clonality observed after nivolumab possibly reflects the evolving molecular heterogeneity in a highly pre-treated disease. An in-deep review of the available literature regarding the role of ICIs in both sporadic and gRRD gliomas was conducted.

Idiopathic stenosis of foramina of Monro in an asymptomatic adult patient: a rare entity radiologists should be aware of.

Bilateral Adult Idiopathic Oclussion of Foramen of Monro is a rare entity, with less than 22 cases published in the literature so far, all of them symptomatic.1 When the symptoms require it, the current first-line treatment is endoscopic foraminoplasty, sometimes associated with septum pellucidum fenestration, although some authors consider that a more conservative treatment in paucisymptomatic patients.2 We report the case of an idiopathic biventricular hydrocephalus found incidentally in an asymptomatic 42-year-old female with temporomandibular joint disfunction. The fact that some patients with Monro foraminal stenosis may be asymptomatic increases the possibility of underdiagnosis, so we consider it a condition that radiologists should be aware of, mainly taking into account the fact that the diagnosis of this entity is usually radiologic3 and the potential complications associated with treatment.

C8-T1 Radiculopathy Due to an Intradural Extramedullary Metastasis of a Pancreatic Neuroendocrine Tumor: Case Report and Review of the Literature.

Pancreatic neuroendocrine tumors (pNETs) are usually well-to-moderately differentiated neuroendocrine tumors (NETs) that most often metastasize to the liver and lymph nodes with other locations being uncommon. We present a case of intradural pNET metastasis and conduct a review of the literature. Forty-five cases, including the case presently reported, of spinal cord compression due to well-differentiated NETs were found: carcinoid (80%), pNET (13.3%), and NETs of unknown primary (6.7%). Seventy-eight percent of cases consisted of extradural compressions from vertebral bone metastases, whereas there were only 5 cases of intradural extramedullary spinal cord compression. Most cases were managed with surgery and/or radiotherapy with a good clinical outcome in the majority. We report the first case of a pNET intradural extramedullary metastasis and conduct the largest review to date of an infrequent complication of well-differentiated NETs such as malignant spinal cord compression. Aggressive local treatment is warranted in most cases because it usually achieves neurologic improvement and symptomatic relief in patients who may still have a long life expectancy.