Combination of Quick Bag and Cryopreservation Enhances Convenience of Mohs Paste

In clinical practice, Mohs paste is used to treat patients with inoperable skin tumors; however, its viscosity and stickiness increase dramatically immediately after preparation. Additionally, this enhanced viscosity and stickiness reduce its usability. In this study, we investigated whether the combination of a polyethylene bag (quick bag) with a narrow nozzle and cryopreservation improves the long-term storage and usability of Mohs’ paste. At 4℃ and 25℃, Mohs paste solidified nine months after preparation, rendering it unrecoverable from the polyethylene bag. In contrast, cryopreservation at –20℃ attenuated the hardening of Mohs paste in the polyethylene bag, and kneading also decreased the viscosity. After nine months of storage, the viscosity of Mohs paste subjected to cryopreservation and kneading was approximately 2.6 Pa∙s in the polyethylene bag. Moreover, tissue invasion with these stored pastes was similar to that with freshly prepared Mohs paste, and it was possible to easily treat the affected area using a narrow nozzle. In conclusion, we found that the combination of a polyethylene bag and cryopreservation allows the Mohs paste to be stored over extended periods and enhances its usability. This method may increase the usefulness of the paste for clinical use.