Feasibility and utility of transbronchial cryobiopsy in precision medicine for lung cancer: Prospective single‐arm study

Cryoprobe is a novel transbronchial biopsy (TBB) tool that yields larger tissue samples than forceps. Pathological diagnosis and biomarker analysis, such as genetic alterations and programmed death‐ligand 1 (PD‐L1) expression, are paramount for precision medicine against lung cancer. We evaluated the safety and usefulness of cryoprobe TBB for lung cancer diagnosis and biomarker analysis. In this single‐center, prospective single‐arm study, patients suspected of having or diagnosed with primary lung cancer underwent cryoprobe TBB using flexible bronchoscopy after conventional forceps TBB from the same lesion. Cryoprobe TBB was performed in 121 patients. The incidence rate of severe bleeding and serious adverse events (4% [90% confidence interval: 2%‐9%]) was significantly lower than the expected rate (20% with 30% threshold, P < 0.01). Combining both central and peripheral lesions, the diagnostic yield rate of cryoprobe samples was 76% and that of forceps samples was 84%. Compared with forceps TBB samples, cryoprobe TBB samples were larger (cryoprobe 15 mm² vs forceps 2 mm²) and resulted in a larger proportion of definite histomorphological diagnosis (cryoprobe 86% vs forceps 74%, P < 0.01), larger amounts of DNA extracted from samples (median: cryoprobe, 1.60 µg vs forceps, 0.58 µg, P = 0.02) and RNA (median: cryoprobe, 0.62 µg vs forceps, 0.17 µg, P < 0.01) extracted from samples, and tended to yield greater rates of PD‐L1 expression >1% (51% vs 42%). In conclusion, cryoprobe is a safe and useful tool for obtaining lung cancer tissue samples of adequate size and quality, which allow morphological diagnosis and biomarker analysis for precision medicine against lung cancer.     

Histological alterations following fine-needle aspiration for parathyroid adenoma: Incidence and diagnostic problems

This study aimed to clarify the histological alterations following fine-needle aspiration for parathyroid adenoma and discuss the occurrence of diagnostic problems. Among the 392 patients with parathyroid adenoma who underwent resection, fine-needle aspiration was performed for 21 (5.1%) parathyroid adenoma nodules. Histological findings that were significantly more frequent in cases that underwent fine-needle aspiration were considered histological alterations following fine-needle aspiration for parathyroid adenoma, including the following six findings: thick fibrous capsule (71.4%), multilayered fibrous capsules (14.3%), capsular pseudo-invasion (42.9%), fibrous bands (57.1%), hemosiderin deposition (14.3%), and tumor implantation (14.3%). Eighteen parathyroid adenoma nodules (85.7%) exhibited one or more of the six findings. Tumor cells and adipocytes entrapped within the thick fibrous capsule were occasionally observed. The fibrous bands were frequently connected to the thick fibrous capsule. The number of passes, duration between fine-needle aspiration and resection, tumor size, and purpose of fine-needle aspiration were not related to the incidence of histological findings. Because of the histological alterations following fine-needle aspiration for parathyroid adenoma that can be easily mistaken for signs of atypical adenoma or parathyroid carcinoma, we recommend that the six findings be excluded from pathological findings indicating atypical adenoma or parathyroid carcinoma in patients with preoperative fine-needle aspiration.