Multiphoton microscopy for rapid histopathological evaluation of kidney tumours.

Abstract

To explore the potential of multiphoton microscopy (MPM) for rapid evaluation and triaging of ex vivo kidney tissue. Fresh neoplastic and non-neoplastic tissues from nephrectomy specimens (n = 40) were imaged with MPM and later submitted for routine histopathology. On MPM, normal kidney architecture was evident and clearly distinguishable from tumour. Forty malignant tumours (20 clear-cell renal cell carcinomas [RCCs], 10 papillary RCCs, five chromophobe RCCs and five papillary urothelial carcinomas [UCs], as diagnosed by haematoxylin and eosin staining) were imaged and subtyped as non-papillary and papillary, based on their architecture. Non-papillary tumours were further classified based on their unique cytoplasmic signatures. Clear-cell RCCs had a predominant population of cells with fat droplets in cytoplasm. Chromophobe RCCs had cells with non-fatty/homogeneous cytoplasm and distinct intra-cytoplasmic granules. Papillary RCCs had single-cell-lined papillae with often abundant histiocytes in their core, whereas PUC had multi-layered urothelium-lined papillae. The diagnostic accuracy of tumour subtyping by two independent uropathologists was 95%. We showed that MPM can reliably differentiate neoplastic from non-neoplastic kidney tissue and subtype kidney tumours in fresh, unprocessed tissue, MPM might therefore be useful as a rapid real-time diagnostic tool for the evaluation of kidney biopsies, and surgical margins in partial nephrectomies, to improve overall patient management.