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RationaleRecent data have demonstrated the superiority of Pembroluzimab over chemotherapy for patients with advanced NSCLC and high (≥50% expression) of PD-L1.1 This has resulted in NICE approving Pembroluzimab as a first line treatment option for patients with advanced NSCLC in June 2017. The original trial however excluded patients with PD-L1 testing on EBUS samples. We therefore conducted a large, multicentre study to clarify whether specimens obtained by EBUS-TBNA were suitable for testing PD-L1 in patients with NSCLC.MethodsNSCLC samples acquired by EBUS-TBNA (29.4%), percutaneous biopsy (31.2%), endobronchial biopsy (13.8%), surgical (21.4%) or other techniques (4.1%) were recorded from 435 consecutive patients with known or suspected lung cancer across 5 centres in England between January 2015 and December 2016.ResultsPD-L1 assessment (using the 22 C3 assay in all cases) was possible in 92.2% of patients undergoing EBUS and there was no difference in success of PD-L1 testing according to modality of tissue acquisition (p=0.18). The frequency of complications from EBUS-TBNA was similar to endobronchial or percutaneous techniques but lower than surgical procedures (5.0% vs 13.8%; p=0.03). PD-L1 expression in the cohort was high (≥50%) in 28.5%, weak (≥1%–50%) in 28.2%, whilst 43.3% of patients were PD-L1 negative. The only statistically significant predictor for PD-L1 expression in multivariate analysis was the presence of brain metastasis at diagnosis (OR 2.02; CI 1.04–3.90). 47 patients (11.4%) were treated with immunotherapy and the response rate was 16.2%. All patients that responded to immunotherapy had high (≥50%) expression of PD-L1.ConclusionsThis large multicentre study demonstrates for the first time that samples obtained by EBUS-TBNA in routine practice are suitable for PD-L1 testing in patients with NSCLC. The presence of brain metastases at diagnosis predicts high PD-L1 expression in this cohort and this new finding should be tested in future clinical trials.ReferenceReck M, Rodrguez-Abreu D, Robinson AG, et al. Pembrolizumab versus Chemotherapy for PD-L1Positive NonSmall-Cell Lung Cancer. N Engl J Med 2016;375(19):1823-33. doi:10.1056/NEJMoa1606774

Although hypoxic pulmonary vasoconstriction is a well-recognized physiological phenomenon it is unusual to observe and assess its efficiency in clinical practice. Here, we report the case of a 50-year-old female who presented with unilateral incomplete bronchial occlusion due to a carcinoid tumor involving the left main bronchus in the absence of atelectasis. Ventilation-perfusion imaging revealed absent ventilation and perfusion to the left lung. She underwent bronchotomy and removal of the tumor. One month after the operation a further ventilation-perfusion lung scan revealed complete restoration of ventilation to the left lung and almost complete recovery of the perfusion. This unusual case demonstrates the marked efficiency of hypoxic pulmonary vasoconstriction at the level of a single lung and its reversible nature following relief of regional hypoxia.

Background: Teratomas are a rare subgroup of CNS germ cell tumors and are histologically classified into mature teratomas, immature teratomas, and teratomas with malignant transformation. CNS teratomas are infrequently found in the posterior fossa and pure mature teratomas of posterior fossa are rare especially in adults. We present a case of a young adult female with a mature teratoma in the cisterna magna. Case Description: A 26-year-old female presented to the neurosurgery clinic with headache, nausea and vomiting for the past 1 year. She was found to have dysdiadochokinesia on neurological examination. Brain magnetic resonance imaging scan showed a-well defined lesion, hyperintense on T1 and hypointense on T2-weighted sequences located within the cisterna magna. She underwent a suboccipital craniotomy with resection of lesion. Histopathology confirmed the diagnosis of mature cystic teratoma. Conclusion: Mature teratomas located in the posterior fossa among adults are rare in the literature. We report the second case of mature teratoma in the cisterna magna of an adult patient.

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