Laparoscopic fluorescence diagnosis of peritoneal metastases from human hepatoblastoma in nude rats

AimFluorescence diagnosis is gaining clinical importance for the detection of malignancies in various medical disciplines. The technique relies on the specific metabolic capacity of a lesion to produce a fluorescent compound. It is still unknown whether pediatric solid tumors like hepatoblastoma (HB) are susceptible to this technique as well.MethodsHuman HB (3 × 106) cells were laparoscopically injected (4 mm scope, 18-G needle) underneath the peritoneum of 7 nude rats (mean weight, 198 g). Tumor growth was allowed for 7 weeks. Photosensitization was induced by peritoneal lavage with aminolevulinic acid (3%). After 3 hours, the animals were investigated with white light laparoscopy (WL) and laparoscopic fluorescence diagnosis (LFD), applying the Storz PDD system. Every suspicious lesion was analyzed by spectrometry and harvested for histology.ResultsEvery tumor seen in WL also demonstrated strong fluorescence during LFD (100%). One micrometastasis, almost invisible in WL, was obviously illuminating in LFD. Spectrometry demonstrated the specific peak of the aminolevulinic acid metabolite protoporphyrin IX at 635 nm and a 6.34-fold increase of the fluorescence intensity. Histology revealed HB in all specimens.ConclusionHuman HB can be detected with LFD in a rat model. This finding opens a wide spectrum of experimental and clinical investigations to evaluate the impact of fluorescence diagnosis for pediatric oncology.