Intraoperative rapid immunohistochemistry with noncontact antibody mixing for undiagnosed pulmonary tumors.

Knowledge of the histologic type and primary origin of pulmonary tumors is essential when preparing a surgical strategy. Intraoperative diagnosis of hematoxylin and eosin (H&E)-stained frozen sections is the gold standard, but reliable pathology requires time-consuming immunohistochemistry (IHC) to distinguish among histological types/organ origins and to analyze molecular status. The aim of this study was to evaluate the clinical reliability of a new rapid-IHC technique for intraoperative diagnosis of pulmonary tumors. In total, 169 patients with undiagnosed pulmonary tumors were enrolled in a multicenter prospective observational study. At three institutes, pulmonary tumor samples were collected through core needle biopsy and/or surgery to determine surgical strategies. Using a new device for rapid IHC, we applied a high-voltage, low-frequency alternating current (AC) field, which mixes the available antibody as the voltage is switched on/off. Rapid IHC can provide tumor histologic type/origin diagnoses within 20 min, as opposed to the 3-6 h required for conventional IHC. No false diagnoses of malignancy were rendered in any of the cases when using simple H&E staining. With H&E staining alone, the overall definitive diagnosis rate, the rate of defined tumor origin, and the rate of determined histological type were 76.92%, 85.80%, and 90.53%, respectively. When rapid IHC was added, those rates were significantly improved to 88.76%, 94.67%, and 91.72%, respectively. By providing prompt and accurate intraoperative histological/molecular analysis, rapid IHC driven by AC mixing could serve as an effective clinical tool guiding the surgical strategy for undiagnosed pulmonary tumors.