Multiphoton microscopy: A novel diagnostic method for solid tumors in a prospective pediatric oncologic cohort, an experimental study.

BACKGROUND: The prognosis of solid pediatric tumors strongly correlates with accurate staging and complete local control. Currently, surgeons rely on macroscopic cues and intraoperative cryosection to determine resection borders. Multiphoton Microscopy (MPM) is a real time technique that allows imaging of tissue without time-consuming tissue processing.

PURPOSE: This pilot study evaluates the diagnostic potential of MPM in pediatric solid tumors compared to routine histopathology.

METHODS: Slides of pediatric tumor samples (nephroblastoma and neuroblastoma [n = 2]; ganglioneuroma, pleuropulmonary blastoma, hepatocellular carcinoma [n = 1]) were prepared to allow direct comparison of MPM with conventional light microscopy. Additionally, we applied MPM to native tumor tissue blocks to evaluate direct visualization of malignant cells through the tumor capsule. Images were interpreted by an attending surgical pathologist. Detectability of tumor-specific features was compared between MPM and conventional histology.

RESULTS: A total of 7 tumors from 7 recruited patients were analyzed. All MPM images were accurate in diagnosing typical criteria of each particular neoplasm. In addition, MPM clearly visualized tumors through the capsule without sectioning or labeling procedures. The quality of MPM was sufficient to make the diagnosis and visualize typical entity-specific architectural changes.

CONCLUSION: MPM is comparable to conventional histopathology in the diagnosis of pediatric solid tumors without the need for fixation or staining. It therefore has tremendous potential for future real-time intraoperative diagnostics and as an alternative to conventional frozen section histopathology.

LEVEL OF EVIDENCE: III.