HydroMark Clip-Guided Cryoablation of a <3-mm Breast Cancer at the Lower Limit of Sonographic Conspicuity in a High-Risk Surgical Patient.

Breast cryoablation is emerging as a minimally invasive local treatment for carefully selected patients with low-risk, early-stage breast cancer. We report the case of a 73-year-old woman with a 3-mm, Nottingham grade 1, estrogen receptor-positive, progesterone receptor-positive, human epidermal growth factor receptor 2 (HER2)-negative invasive ductal carcinoma (cT1a cN0, stage IA) who was considered a poor surgical candidate because of severe pulmonary disease, chronic liver disease, active tobacco and alcohol use, peripheral arterial disease, and ongoing antiplatelet therapy. Following ultrasound-guided core needle biopsy, the tumor became poorly conspicuous, while the sonographically visible HydroMark clip (Devicor Medical Products, Inc., Cincinnati, OH) remained centered within the biopsy site. The clip was therefore used as the primary landmark for probe positioning during percutaneous ultrasound-guided cryoablation. Real-time ultrasonography confirmed complete ice-ball coverage of the clip-centered target, and hydrodissection maintained a protective plane between the ablation zone and the skin. The procedure was completed without complication. At the two-month follow-up, contrast-enhanced breast MRI and targeted ultrasound demonstrated expected post-ablation changes without suspicious residual enhancement or a residual mass. This case demonstrates that a HydroMark clip can serve as a reliable sonographic landmark for target localization and probe positioning when a small tumor becomes poorly conspicuous after biopsy. Although early imaging findings were favorable, longer-term follow-up is needed to confirm durable local tumor control.