In this issue

Excerpt

This issue once again contains a series of papers illustrating the different faces of pathology: observationally descriptive, but also oriented towards pathogenesis or testing reproducibility of purported prognostic parameters and biomarker validation. A typical observational paper is that of Queipo et al. (DOI https://​doi.​org/​10.​1007/​s00428-018-2389-y) who elaborate on pigmented microcystic chromophobe renal cell carcinoma, a variant of chromophobe renal cell carcinoma first described some 20 years ago and since then reported by only one or two groups. The morphological spectrum of renal cell carcinoma is quite remarkable and with the advent of relatively comprehensive molecular analysis some histological patterns have been associated with specific molecular characteristics. This is not the case for the pigmented microcystic variant of chromophobe renal cell carcinoma, even though the authors do report on copy number variations of chromosomes 7 and 17 by in situ hybridization. Clinical course of this variant is as that of other chromophobe renal cell carcinomas: rather indolent even though in one case sarcomatoid transformation was found along with metastases. The study raises the question of the relevance of subdividing disease entities based upon morphological characteristics only, without clinical significance and with unknown biological background. Time will tell if this subtype will survive. …