Needle tract seeding after endobronchial ultrasound-guided intranodal forceps biopsy and cryobiopsy: a case report.

Background: Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (EBUS-TBNA) is a standard procedure for diagnosing intrathoracic lymphadenopathy; however, it has limitations in diagnostic yield and sampling adequacy for certain conditions. To address this issue, EBUS-guided intranodal forceps biopsy (EBUS-IFB) and cryobiopsy (EBUS-CRYO) have been performed. Both techniques require the creation of a tract for the insertion of forceps or cryoprobes into the lymph nodes. However, potential adverse events associated with this tract remain unclear. Needle tract seeding (NTS), which is defined as the implantation of tumor cells along the puncture tract, is a rare but clinically significant complication of gastrointestinal procedures. However, its occurrence after bronchoscopy has rarely been reported. This report describes a rare case of NTS following EBUS-IFB and EBUS-CRYO.

Case description: An 83-year-old woman with lung adenocarcinoma harboring MET exon 14 skipping mutation presented with right upper lobe nodules and bilateral mediastinal lymphadenopathy. The initial EBUS-TBNA yielded insufficient specimens for molecular testing. Subsequent EBUS-IFB and mediastinal cryobiopsy provided sufficient specimens for definitive diagnosis. Twenty-nine days after the procedure, computed tomography revealed rapid growth of the right upper lobe nodules and a tracheal mass at the biopsy site, consistent with NTS. Despite this complication, the patient demonstrated a marked response to tepotinib therapy, with significant regression of both the lung and tracheal lesions.

Conclusions: This case highlights the need for increased awareness of NTS following advanced biopsy techniques. Tumor-related factors such as high malignancy and necrosis, combined with procedural elements, likely contribute to its occurrence. Bronchoscopists should carefully evaluate the procedural approaches and follow-up protocols to mitigate this risk and ensure early detection.