The WHO 2022 underlines that histological characteristics remain the gold standard for the classification and diagnosis of urothelial tract tumors.
The new classification has tried to give a good description of each tumor type ordered from benign to malignant. Some chapters have been split, some have been ordered in a different manner. One thing which is really important in 2022 is that we have an update of the nomeclature which underlines that the diagnostic of subtypes is surgical pathology and variant is related to molecular pathology.
The classifications have remained mainly the same. Urothelial dysplasia is still in the WHO, hyperplasia or urothelial proliferation of unknown malignant potential has not found way into the classification.
The grading is still PUNLMP low grade and high grade. Special attention is paid to inverted histology and heterogeneous grades. T1 staging is, although recommended, still not resolved.
The subtypes have been extended and arranged differently according to the latest research results. New is the distribution of neuroendocrine tumors in a separate chapter. Molecular issues are discussed in an abundant manner, urine cytology and MRI imaging are also discussed.
The differentiation between reactive and neoplastic remains challenging. Clinical history is of major interest in case of doubts it might be useful to search help from more experienced pathologists in order to discuss the lesion.