A Molecular Array for 10-second Diagnosis of Common Spinal Tumour Types with Picosecond Infrared Laser Mass Spectrometry.

Background: Improving the surgical outcomes for commonly occurring spinal neoplasms of extradural and intradural extramedullary origins requires precise intraoperative diagnosis provided by highly trained neuropathologists.

Methods: Through a retrospective study of n=319 patient specimens, verified where appropriate by learning curve analysis to be sufficient for statistically significant observations, we aimed to assess the utility of 10-second picosecond infrared laser mass spectrometry (PIRL-MS) for non-subjective diagnosis of major spinal tumour types of metastatic carcinoma, schwannoma and meningiomas.

Results: The sensitivity and specificity values of spinal tumour type diagnosis (based on n=182 independent specimens) were (93±1)% and (97±2)%, respectively. This classification utilizes n=41 cellular lipids including phosphatidylcholines, sphingomyelins, phosphatidylethanolamines, and ceramides whose identities were established using high-resolution tandem mass spectrometry. Furthermore, the accuracy of diagnosis of a model that contained n=97 meningioma and n=106 schwannoma was not drastically influenced by the presence of n=54 additional intradural extramedullary spinal neoplasms of myxopapillary ependymoma, neurofibroma, paraganglioma and solitary fibrous tumour types in the differential diagnosis, confirming the generalizability and robustness of the identified molecular array in rendering correct classification even in the presence of data not seen previously by the model.

Conclusions: The identified lipids form a 'molecular array' for robust diagnosis of meningioma and schwannoma tumours by non-pathologists in a manner similar to genomic, transcriptomic or methylomic arrays used to diagnose brain cancer types, albeit on a much faster timescale of seconds as opposed to hours.