Background and study aims Recently, a new Franseen design endoscopic ultrasound-guided fine-needle biopsy (EUS-FNB) needle was developed with the goal of providing more tissue for histology. We compared the tissue adequacy rate and nucleic acid yield of 22G EUS-FNB vs. 22G endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA), in solid gastrointestinal and extra-intestinal lesions. Patients and methods We conducted a randomized crossover study and recruited 36 patients. We performed three passes for pancreatic lesions and two passes for other lesions, using each needle. We blinded the pathologist to needle assignment. We assessed the diagnostic tissue adequacy rate and compared the total tissue area, diagnostic tissue area, and desmoplastic stroma (DS) area in cases of carcinoma. We also examined the nucleic acid yield of the two needles in pancreatic lesions. Results The lesions included 20 pancreatic masses (55 %), six gastric subepithelial lesions (17 %), five lymph nodes (14 %) and five other abdominal masses (14 %). Mean ± SD lesion size was 3.8 ± 2.0 cm. The final diagnosis was malignant in 27 lesions (75 %) and benign in nine lesions (25 %). We found EUS-FNB procured significantly more median total tissue area (5.2 mm2 vs. 1.9 mm2, P < 0.001), diagnostic tissue area (2.2 mm2 vs. 0.9 mm2, P = 0.029), and DS area (2 mm2 vs. 0.1 mm2, P = 0.001) in lesions diagnosed as carcinoma (n = 23), as compared to EUS-FNA. In pancreatic lesions, EUS-FNB obtained significantly more nucleic acid than EUS-FNA (median; 4,085 ng vs. 2912 ng, P = 0.02). There was no difference in the cellblock or rapid on-site cytological evaluation (ROSE) diagnostic yield between the needles. Conclusion The 22G EUS-FNB provides more histological core tissue and adequate nucleic acid yield compared to 22G EUS-FNA. In this study, the diagnostic performance was similar between the needles

Isocitrate dehydrogenase (IDH) mutations are a common event in secondary glioblastoma multiforme and lower-grade adult infiltrative astrocytomas and independently confer a better prognosis [1,2]. These are highly conserved mutations during glioma progression and thus also a useful diagnostic marker amenable to modern molecular sequencing methods. These mutations can even be detected in sites distant from the primary tumour. We use an illustrative case of a patient with radiologically suspected recurrent astrocytoma and negative histology, but positive IDH-mutated tumour DNA detected within CSF. Our results demonstrated the usefulness of liquid biopsy for recurrent glioma within the context of equivocal or negative histopathological results, whilst also showing the ability to detect a de-novo IDH-2 mutation not present in the previous resection. Building on this ‘proof-of-concept’ result, we also take the opportunity to briefly review the current literature describing the various liquid biopsy substrates available to diagnose infiltrative gliomas, namely the study of circulating tumour DNA, circulating tumour cells, and extracellular vesicles. We outline the current challenges and prospects of liquid biopsies in these tumours and suggest that more studies are required to overcome these challenges and harness the potential benefits of liquid biopsies in guiding our management of gliomas.

potential for misdiagnosis both clinically and histologically. Here we present a case from our institution of a 27-year-old man with a testicular low grade serous carcinoma, arising from a serous borderline tumour, with a discussion of the histologic, immunohistochemical and molecular findings. 1-3 References 1. Lin MS, Ayala AG, Ro JY. Ovarian-type tumours (Mullerian tumors) of the testis: clinicopathologic findings with recent advances. Ann Urol Oncol 2019; 2: 36-45.